Emerson Computer Hardware MVME147 User Manual

GENERAL INFORMATION

Introduction

The MVME147 MPU VMEmodule contains a port to the Small Computer

Systems Interface (SCSI) bus. The hardware interface is the WD33C93 SCSI

interface controller.

To relieve you of having to follow SCSI bus protocol, the SCSI firmware allows

you to pass commands to the bus through high level command packets.

Standard command packets are furnished, as well as custom SCSI sequence

packets that you may easily modify to fit particular applications. With this

method, the firmware interface can greatly speed up your software

development cycle.

The SCSI firmware resides in two 128K x 8 EPROMs and is co-resident with

MVME147Bug, the debug monitor for the MVME147 MPU VMEmodule.

Features

The SCSI firmware offers the following features:

❏

Custom SCSI sequence packets that allow creation of customized

functions

❏

TARGET role

Multitasking -- up to 64 concurrent peripheral devices

High level support of SCSI devices

Interrupt mode allows real-time applications

Polled mode -- non-interrupt operation

DMA with memory/ scatter/ gather

Multiple-user interface allows concurrent operation through independent

drivers

❏

Six entry points

Thirty-one "canned" or standard function packets

Modes of Operation

When using the SCSI firmware, you have a choice of two modes of operation:

Interrupt mode and polled mode.

MVME147 SCSI Firmware Entry Points

6. $FFFE079A (RTE entry)

Within the SCSI firmware, which can stand alone without

the debug monitor, the first six longwords are the branch

table entries referenced above. The hex offsets provided

reside within the non-volatile RAM.

Note

The following are descriptions of the six entry points. For more detailed

descriptions of their use, refer to the Interface Rules for Multiple Callers section

in Chapter 5.

$FFFE077C: COMMAND ENTRY

Branches to FUNNEL entry.

$FFFE0782: REACTIVATION ENTRY

Branches to FUNNEL entry. All preprocessed commands are

activated in the interrupt service routine through software

interrupt.

$FFFE0788: INTERRUPT ENTRY

This entry point is used as the interrupt service routine

address for vectors on the MVME147 module. Vector $45

(offset $114 from VBR) is the WD33C93 interrupt vector used

by the SCSI firmware. Vector $46 (offset $118 from VBR) is the

DMA channel interrupt vector and vector $4B (offset $12C

from VBR) is the software interrupt vector used by the SCSI

firmware to service queued commands.

The SCSI firmware initializes these vectors.

Note

The following intermediate return resumes with an

interrupt which gives

control to the interrupt entry:

$02: WAIT FOR INTERRUPT (OPEN)

Intermediate status indicating that an WD33C93 interrupt

brings the processor control back to the SCSI firmware. The

MVME147 can accept more commands if it is currently

disconnected from the SCSI bus (refer to the SCSI Firmware

1-3

GENERAL INFORMATION

Interrupt Structure paragraph in Chapter 4) or SCSI bus

activity is slowed down. Additional commands may be sent

to the SCSI firmware for a different peripheral device.

$FFFE078E: FUNNEL COMMAND ENTRY

This entry point is used by applications that require multiple

interfaces to the SCSI firmware. Unlike the single user

command entry, you may issue commands anytime the

firmware does not require an RTE to be performed. If an RTE

is required, and you wish to send a command at the same

time, you may accomplish both by using the RTE entry

(described below). The use of the FUNNEL command entry

causes the FUNNEL module to examine the state of the SCSI

bus, determine if the bus is currently in use, and send the

command to the bus if it is not in use. If the bus is currently

in use, the FUNNEL module checks if the device is not busy

so it can preprocess or queue the command and return to the

caller with an intermediate status of $A002. This

preprocessed or queued command is processed and sent to

the SCSI bus when the bus is free.

$FFFE0794: COME-AGAIN ENTRY

Branches to FUNNEL entry. All the queued commands are

serviced in the interrupt service routine through software

interrupt.

$FFFE079A: RTE ENTRY

The SCSI firmware notifies the user/ caller that an RTE

instruction needs to be executed by the RTE bit (13) of the

returned status word. If this bit is 0, an RTE is required; if this

bit is 1, an RTE is not required (the SCSI firmware does not

execute the RTE instruction so as not to preempt a task in a

VERSAdos or SYSTEM V/ 68 environment). SCSI firmware

users may inherit an RTE from another caller because of the

multiple caller interface. When an RTE is inherited from

another caller, the use of the RTE entry may be required to

send down a new command before executing an RTE

instruction.

Equipment Supported

The following list shows the controller type assignments for SCSI controllers

explicitly supported by the SCSI firmware, and the drives supported by each.

/ f3Note, however, that Motorola does not necessarily endorse or recommend

1-4

Equipment Supported

any particular controller, nor does Motorola assume responsibility for the

operation of equipment manufactured by non-Motorola companies. Refer to

Appendix A for information on how to use this firmware program.

CONTROLLE

DEVICE

TYPE

PART

MANUFACTUR

ER/MODEL

CODE

NUMBER

NOTES

Floppy

TEAC FD235J

Winchester

Televideo

1002921-1B

1,2,3

7000/ 7400/ 3500

Floppy

Tape

Winchester

Common

Command Set

1,2,3

Floppy

Winchester

Seagate WREN

III 94161

77774620

75912134

1,2

Winchester

Seagate WREN

IIIHH 94211

Seagate SWIFT

94351-126

Seagate SWIFT

94351-201

Winchester

Streaming

Micropolis 1375 900475-11-2B

1,2

Archive Viper

2060s

22100-007

Tape

Streaming

Archive Viper

2150s

22300-004

1,2

Tape

Streaming

Tanberg 3620

(8533) 60Mb

Tape

Streaming

Tanberg 3640

(8534) 120Mb

Tape

1-5

GENERAL INFORMATION

CONTROLLE

DEVICE

PART

MANUFACTUR

ER/MODEL

CODE

TYPE

Streaming

NUMBER

NOTES

Tanberg 3660

(8535) 150Mb

Tape

Cassette

TEAC MT-

2ST/ 45S2

Tape

CONTROLLE

DEVICE

PART

MANUFACTUR

ER/MODEL

CODE

TYPE

NUMBER

NOTES

Winchester

Seagate WREN

IV 94171

77777000

1,2

Winchester

Seagate WREN V 77777750

94181

Winchester

Maxtor 4380S

Maxtor 8760S

Seagate ST

157N/ M

1,2,5

Winchester

Seagate ST

125N/ M

1,2,5

Seagate ST

1096N

Seagate ST

296N/ M

Winchester

1/ 2" Tape

Miniscribe

1,2

Kennedy

9612/ 9662

U92-9662-0004

1/ 2" Tape

HP 88780A

Winchester

Synchronous

Common

Command Set

1-6

Equipment Supported

CONTROLLE

DEVICE

TYPE

PART

MANUFACTUR

ER/MODEL

CODE

NUMBER

NOTES

Floppy

8mm Tape

2,3

Exabyte EXB-

8200

820010-009

Devices Supported Under Common Command Set

Winchester

Televideo

1,2

7000/ 7400/ 3500

Floppy

Televideo

7000/ 7400/ 3500

1002921-1B

77774620

1,2,3

1,2

Winchester

Seagate WREN

III 94161

Seagate WREN

IIIHH 94211

1,2

Winchester

Micropolis 1375 900475-11-2B

1,2

Seagate WREN

IV 94171

77777000

1,2,4

Winchester

Seagate WREN V 77777750

94181

2,4

1,2

Seagate SWIFT

94351-126

75912134

Seagate SWIFT

94351-201

Winchester

Maxtor 4380S

Maxtor 8760S

2,4

Devices Supported Under Synchronous Common Command Set

Winchester

Seagate WREN V 77777750

94181

2,4

Winchester

Maxtor 4380S

Maxtor 8760S

2,4

Supported in firmware revision 1.0 and later.

Supported in firmware revision 2.0 and later.

TE:

1-7

GENERAL INFORMATION

Common Command Set for floppy matches SCSI II rather than revision 17B.

Under Common Command Set the cache is not enabled on these devices.

Seagate / M means Motorola proprietary.

Firmware assembly order number is: 966096. Order number for tape drives is

(85xx) as shown with drive type. Order from: Tanberg Data A/ S, Data

Storage Division, P.O. Box 9, Korsvoll N-0808, Oslo 8, Norway, Phone +47 2 18

90 90 or Tanberg Data Tech. Center, 1077 Business Center Circle, Newbury

Park, CA 91320, Phone +1 (805) 375-2500.

Related Documentation

The publications listed in the following table may provide additional helpful

information. If not shipped with this product, they may be purchased from

Motorola’s Literature Distribution Center, 616 West 24th Street, Tempe, AZ

85282; telephone (602) 994-6561. Non-Motorola documents may be obtained

from the sources listed.

MOTOROLA

DOCUMENT TITLE

PUBLICATION NUMBER

MVME147

MVME147 MPU VMEmodule User’s Manual

MVME147S MPU VMEmodule User’s

Manual

MVME147S

MVME147Bug Debugging Package User’s

Manual

MVME147BUG

MVME712A

MVME712A/ MVME712AM/ MVME712B

Transition

Module and MVME147P2 Adapter Board

User’s Manual

MVME712M Transition Module and

MVME147P2

MVME712M

Adapter Board User’s Manual

1-8

Manual Terminology

MOTOROLA

PUBLICATION NUMBER

M68000UM

DOCUMENT TITLE

M68000 16/ 32-Bit Microprocessor

Programmer’s

Reference Manual

M68000 Family VERSAdos System Facilities

Reference Manual

M68KVSF

VERSAdos to VME Hardware and Software

Configuration User’s Manual

MVMEDOS

NOTE:

Although not shown in the above list, each Motorola

Computer Group manual publication number is suffixed with

characters which represent the revision level of the document,

such as / D2 (the second revision of a manual); supplement

bears the same number as the manual but has a suffix such as

/ A1 (the first supplement to the manual).

The following publications are available from the sources indicated.

SCSI Guide Book; Adaptive Data Systems, Inc., 2627 Pomona Boulevard,

Pomona, CA 91768

SCSI Small Computer Systems Interface; draft X3T9.2/ 82-2, Revision 14;

Computer and business Equipment Manufacturers Association, 311 First

Street, N.W., Suite 500, Washington, D.C. 20001

WD33C92 and WD33C93 SCSI Bus Interface Controller Data Manual; Western

Digital, 2445 McCabe Way, Irvine, CA 92714.

Common Command Set (CCS) of the Small Computer System Interface (SCSI)

X3T9.2/ 85-52 - Revision 4B; Computer and Business Equipment

Manufacturer’s Association, 311 First Street, N.W., Suite 500, Washington D.C.

20001

Manual Terminology

Throughout this manual, a convention has been maintained whereby data and

address parameters are preceded by a character which specifies the numeric

format as follows:

1-9

GENERAL INFORMATION

dollar

specifies a hexadecimal

number

percent

specifies a binary number

specifies a decimal number

ampersand

Unless otherwise specified, all address references are in hexadecimal

throughout this manual.

An asterisk (*) following the signal name for signals which are level significant

denotes that the signal is true or valid when the signal is low.

An asterisk (*) following the signal name for signals which are edge significant

denotes that the actions initiated by that signal occur on high to low transition.

In this manual, assertion and negation are used to specify forcing a signal to a

particular state. In particular, assertion and assert refer to a signal that is active

or true; negation and negate indicate a signal that is inactive or false. These

terms are used independently of the voltage level (high or low) that they

represent.

1-10

CUSTOM SCSI PACKETS

Introduction

The SCSI firmware requests "canned" functions from SCSI disk controllers and

from SCSI tape controllers. Some of these functions are disk read and write,

disk format, tape read and write, and tape positioning operations. The

"canned" functions are only provided for the supported SCSI devices that are

listed in the Equipment Supported section in Chapter 1.

If you want to perform a function that is not "canned", or you want to

communicate with SCSI devices that are not supported by the SCSI firmware,

you do not have to rewrite the SCSI firmware. Any SCSI operation may be

performed through the use of the custom SCSI packet.

A custom SCSI packet may be used for a variety of needs. Following are some

typical needs:

1. You need to perform a command on a supported SCSI disk controller that

is not "canned" in the SCSI firmware. (For example, an offline COPY

command is not supported directly by the SCSI firmware. You may

perform this COPY command through the custom SCSI packet.)

2. You wish to interface the MVME147 module to a SCSI optical disk

controller.

3. You wish to request linked commands from a disk controller.

There are three classes of custom SCSI packets, described in the following

sections. They are:

Initiator role custom packet

TARGET enable custom packet

TARGET sequence custom packet

Initiator Role Custom Packet

The initiator role custom packet is shown in the following table.

Even Byte \

Odd Byte \

CUSTOM SCSI PACKETS

+$00

+$02

+$04

+$06

+$08

+$0A

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Script Pointer (MSW)

Script Pointer (LSW)

Command Table Pointer (MSW) (Note 2)

Command Table Pointer (LSW) (Note 2)

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

Flag = 0

Scatter/ Gather Count

Function Code (1C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Retry Count

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

xxxxxxxx

Script pointer (MSW)

Script pointer (LSW)

Command table

pointer (MSW) (Note

$0A

$0C

xxxxxxxx

00000000

xxxxxxxx

00000000

Command table

pointer (LSW) (Note

Reserved

2-2

Initiator Role Custom Packet

$0E

00000000

Initiator role

(TARGET

enable/ sequence bit

undefined)

Reserved

$0F

$10

00000000

xxxxxxxx

Scatter/ gather entry

count. No retry

on firmware if

scatter/ gather DMA

is used

because command

scatter/ gather table

could

be modified after the

command is complete

if disconnect/ reselect

occurred.

$12

$14

$15

00000000

00011100

00000000

Reserved

SCSI function ($1C =

custom SCSI )

$16

$17

$18

00000xxx

xxxxxxxx

Interrupt level (7 to

0)(0 = polled mode)

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

00000000

0000xxxx

Reserved

Retry count --

number of SCSI

command

retries (refer to

scatter/ gather retry

count

above)

2-3

CUSTOM SCSI PACKETS

Refer to Chapter 3.

NOTES:

Command Table = 384 bytes

RAM work area.

This first class is used for command execution and/ or message passing

through the MVME147 SCSI firmware while the module is playing the

initiator role. According to SCSI definition, an initiator is a SCSI device

(usually a host system) which requests an operation to be performed by

another SCSI device; a TARGET is a SCSI device which performs an operation

requested by an initiator. Initiator role custom packets request operations to

be performed by other SCSI devices. For the initiator role, certain data

structures are needed by the SCSI firmware. These are:

1. SCRIPT: A "script" is a sequence of SCSI bus phases that the initiator

expects the TARGET to perform when executing a requested command.

For example, a disk read (under SCSI rules) would typically require the

following SCSI bus phases:

MESSAGE-OUT: The IDENTIFY message is sent from the initiator to the

TARGET. This message contains the identification of the desired logical

unit of the selected disk controller that the initiator wishes to read. The

message also indicates whether the initiator is capable of reselection.

COMMAND: The Command Descriptor Block (CDB) is sent during the

command phase to specify the block number to read, the logical unit to

read from, the number of blocks to read, and whether the command is

linked.

DATA-IN: The actual data is transferred from the TARGET to the initiator

during the data-in phase.

STATUS: The disk controller sends the status of the command that was

executed during this phase.

MESSAGE-IN: During this phase, the disk controller sends a message

describing the execution of the command it just executed. The linked

command information would appear in the message sent during this

phase, for example.

BUS DISCONNECT: After a disk controller sends a command complete

message, it disconnects from the SCSI bus by releasing the BSY* signal.

The justification for a script is as follows. On the SCSI bus, the TARGET

is always the SCSI device that dictates the sequence of bus phases that

occurs during a communication with the initiator (this communication is

2-4

Initiator Role Custom Packet

commonly called a "thread"). The script allows the SCSI firmware to

follow the TARGET bus sequences and also allows the firmware to resume

a disconnected thread once a disconnect/ reselect occurs. Because the SBC

allows "multithreading" of SCSI commands on the SCSI bus, a script is

necessary to resume any disconnected threads. Without a script, the SCSI

firmware would not have any way to check whether the TARGET

performed the command that was requested through the CDB.

The following table gives the possible SCSI bus phases.

PHASE

Bus Free

DIRECTION

NOTES

No activity on the bus. SEL* and BSY* are not

activated.

Arbitration

SCSI devices arbitrate for the use of the bus by

activating BSY* and their ID.

(Re)Selection

One SCSI device selects another device by

activating SEL* along with its ID and the ID for

the other device.

Information Transfer Phases: Command

initiator

to TARGET

A command

tells the

TARGET

what is

requested by

the initiator.

The CDB is

passed

during this

phase.

Status

TARGET

to initiator

The status of a particular command is passed to

initiator. Examples: good, busy, check.

Data

TARGET

to initiator

Data is transferred from the TARGET to the

initiator as a result of a data phase requested in

the CDB.

Data

out

initiator

to TARGET

Data is transferred from the initiator to the

TARGET as a result of a data phase requested in

the CDB.

Message

TARGET

to initiator

Messages are sent to the initiator to send bus,

command, and controller information.

Examples: command complete, save data

pointer, restore data pointer, message reject.

2-5

CUSTOM SCSI PACKETS

PHASE

Message

out

DIRECTION

NOTES

initiator

to TARGET

Messages are sent to the TARGET to send bus,

command, and controller information.

Examples: identify, initiator detected error,

abort, device reset.

Scripts only specify the information transfer phases. The bus free, arbitration,

and selection phases do not need to be specified in a script. The script codes

that are understood by the MVME147 SCSI firmware are listed in the

following table. (Note that TARGET role scripts are described in the Target

Sequence Custom Packet section in this chapter.

CODE

BUS PHASES

END OF SCRIPT

ROLE

$00

Initiator

DISCONNECT

TARGET

$04

$08

$0C

$10

$14

$18

$1C

COMMAND PHASE

DATA-OUT PHASE

DATA-IN PHASE

STATUS PHASE

MESSAGE-OUT PHASE

MESSAGE-IN PHASE

END OF SCRIPT

NOT DEFINED

Initiator and TARGET

TARGET

Initiator

$20

$24

$28

TARGET WAIT,

TARGET

NO DISCONNECT

TARGET WAIT,

TARGET

DISCONNECT

TARGET WAIT,

NO DISCONNECT

DATA RECEIVED

TARGET WAIT,

$2C

TARGET

DISCONNECT

DATA RECEIVED

2-6

Initiator Role Custom Packet

If you suspect data integrity error, you can set up the SCSI script to execute the

data phase and then disconnect from the bus (script code 0x2c) or just return

as an intermediate return without disconnect from the bus (script code 0x28).

Firmware executes the data phase and then returns the firmware parity error

status, if any, command packet, and command table back to you.

You can examine the data as well as the firmware status to decide what SCSI

status should be returned to initiator. After the status is determined, a new

TARGET sequence command packet needs to be sent to firmware with status,

message (for message-in phase), and proper scripts to complete the SCSI bus

command.

For the previous disk read example, the script would be:

$14,$04,$0C,$10,$18,$00.

The above sequence of codes may be written anywhere in the MVME147-

accessible space. It may even be ROMed. The script pointer in the custom

SCSI packet is the address of the first entry of the script. In the example, it

would point to the $14. Therefore, the message-out phase should always be

the first phase in any initiator script.

2. COMMAND TABLE (384 bytes of RAM). The second data structure

required by the SCSI firmware for the execution of a custom SCSI packet

is a Command Table.

For unsupported controllers, the control of certain functions (parity checking,

DMA, linked commands, SCSI rules, DMA scatter/ gather, SYNC/ ASYNC

transfer) is dictated to the firmware through the status/ flag byte of the

Command Table.

The CDB is one of the pieces of the command table. The user of the initiator

role custom SCSI packet loads the CDB to be passed to the SCSI target that is

to be selected. The initiator role custom SCSI packet has a Command Table

pointer which is the address of the first word of this data structure. Unlike the

script, the Command Table must be in MVME147-accessible RAM because the

firmware writes to portions of the table. All the user accessible pieces of the

Command Table are shown in the following table.

Even Byte \

Odd Byte \

2-7

CUSTOM SCSI PACKETS

+$00

Status/ Flag Byte

Retry Count (00)

+$02

Link Pointer (MSW)

Link Pointer (LSW)

Command Length

+$04

+$06

+$08

SCSI Command Descriptor Block (CDB)

+$0A

+$0C

+$0E

+$10

+$12

+$14

SCSI Status

Initiator SCSI Address (0 to 7)

+$16

Data Length (MSW)

Data Length (LSW)

Data Pointer (MSW) (Note 1)

Data Pointer (LSW) (Note 1)

Message-In Length

Message-In Pointer (MSW)

Message-In Pointer (LSW)

Message-Out Length

Message-Out Pointer (MSW)

Message-Out Pointer (LSW)

Reserved

+$18

+$1A

+$1C

+$1E

+$20

+$22

+$24

+$26

+$28

+$2A

+$2C

Reserved

+$60

+$62

Sector Number in Error (MSW)

Sector Number in Error (LSW)

+$64

+$66

SCSI Controller Status

Transfer Address

2-8

Initiator Role Custom Packet

Even Byte \

Odd Byte \

+$68

Transfer Address

+$6A

+$6C

+$6E

+$70

+$72

+$74

Command

Offset

Sense Data Block

+$9E

$00

Sense Data Block

xxxxxxxx

0.......

Status/ flag byte

Lnk -- link flag bit

disabled

1.......

Lnk -- link command

tables, support

linked commands

Parity disabled

.0......

.1......

Parity enabled --

MVME147 checks

SCSI

bus parity

DMA on

..0.....

..1.....

DMA off flag --

disable DMA for data

out/ in

...0....

CSCSI -- custom

sequence flag: checks

2-9

CUSTOM SCSI PACKETS

status (Note 2)

...1....

CSCSI -- does not

check SCSI status

(Note 2)

....0...

....1...

SCSI firmware uses

SCSI rules (Note 3)

SASI mode flag --

firmware uses SASI

rules (Note 3)

.....1..

SG -- scatter/ gather

enable, use data

points to

scatter/ gather table.

During

custom SCSI packet,

you have to set this

bit if scatter/ gather

DMA operation is

required

.....0..

......1.

SG -- scatter/ gather

disable

SYNC -- synchronous

transfers enable

On INITIATOR role,

SCSI firmware

initiates synchronous

data transfer

request.

On TARGET role,

SCSI firmware

initiates synchronous

data transfer

request IF initiator

DOES NOT do so

before first data

phase.

2-10

Initiator Role Custom Packet

......0.

ASYNC --

asynchronous

transfers enable

$01

$02

00000000

xxxxxxxx

Retry count (must be

00)

xxxxxxxx

Link pointer (MSW) --

for linked commands.

Valid only if link flag

bit = 1

$04

$06

xxxxxxxx

Link pointer (LSW)

Command length --

length of the CDB

(in bytes)

$08

xxxxxxxx

SCSI command

descriptor block

(CDB)

SCSI draft revision

17B allows 12 bytes

maximum length

(Note 4)

$0A

$0C

$0E

$10

$12

$14

xxxxxxxx

SCSI (CDB)

SCSI status

On INITIATOR role,

this is the copy of

status on

$64.

On TARGET role, you

can set SCSI status

here.

Bit 0(LSB), 5 and 6 is

vendor unique. Bit 7

is reserved. The

status set here is

ORed with

2-11

CUSTOM SCSI PACKETS

the firmware status

($64) and sent to

initiator.

If you determine to

use bit 1-4, such as

data

parity error, the

firmware non-zero

status on

bit 1-4 has higher

priority. You should

load

this byte with the

appropriate status

and set

up the SCSI script for

status phase before

the

target sequence

packet is sent.

$15

$16

xxxxxxxx

Initiator SCSI address

in TARGET mode (0

to 7)

(only used in

TARGET mode)

xxxxxxxx

Data length (MSW) --

number of bytes

expected during data-

in or data-out phase

$18

xxxxxxxx

Data length (LSW)

$1A

Data pointer (MSW) -

- to memory area

where firmware reads

(data out) or writes

(data-in) (contiguous

buffer)

$1C

2-12

xxxxxxxx

Data pointer (LSW)

Initiator Role Custom Packet

$1E

$20

xxxxxxxx

Message-in length --

bytes expected

during message-in

(max=258 for

extended

messages)

Message-in pointer

(MSW) -- to RAM

buffer where

firmware stores

received

messages

$22

$24

xxxxxxxx

Message-in pointer

(LSW)

Message-out length --

bytes expected

to be transferred in

message-out phase,

has to be non-zero if

message-out phase

is required (max=258

for extended

messages)

$26

$28

xxxxxxxx

Message-out pointer

(MSW) -- to RAM

buffer where

firmware takes

messages to

transfer to TARGET

xxxxxxxx

Message-out pointer

(LSW)

$2A

xxxxxxxx

Reserved

$2C

xxxxxxxx

$60

xxxxxxxx

Sector number in

error (MSW)

2-13

CUSTOM SCSI PACKETS

$62

$64

xxxxxxxx

Sector number in

error (LSW)

xxxxxxxx

Initiator role - Status

byte from SCSI

controller

(unchanged)

TARGET role -

firmware determined

SCSI

status

$65

$66

xxxxxxxx

Reserved

xxxxxxxx

Transfer address -- for

a read or write.

This is the address of

the next byte to be

transferred.

$68

xxxxxxxx

Transfer address -- for

a read or write.

This is the memory

address of the next

byte to be transferred.

$72

xxxxxxxx

Command error

status byte (valid

following

a command error

$0B) -- SCSI

command in

error.

$73

$74

xxxxxxxx

Offset within packet.

xxxxxxxx

Sense data block

(controller-

dependent).

This is the

information returned

by the

2-14

Initiator Role Custom Packet

controller following a

check status and

a request sense data

command. Valid

information if bit 14

(additional status)

is set.

This block is

firmware private area

and only

used on the

INITIATOR role.

$9E

xxxxxxxx

Sense data block

Points to scatter/ gather table if scatter/ gather bit = 1 in byte 0.

NOTE

If = 0 and if status is "check", SCSI firmware interprets returned SCSI

status, and sends a request sense command to the controller; if status is =

busy, infinite retries are performed. If = 1, SCSI firmware does not read

the SCSI status from the command table, and returned status word in the

packet reflects only firmware status.

Must be 0. MVME147 SCSI firmware ONLY supports SCSI devices.

In TARGET mode, the CDBs is received from the SCSI bus and it will be

returned to the user without any modification with CDB length. When a

target LUN is not enabled or when ’target device reset’ or ’abort’ message

is received, the CDB received by the target role firmware will not be

returned to the user. Instead, a error code will be returned.

Example: Sending linked commands to a disk controller

You intend to implement a read-modify-write function for your particular

operating system. The benefit of linking commands on the SCSI bus is a better

utilization of bus bandwidth. When two commands are linked, the TARGET

does not disconnect between commands. After the message-in phase

completes one command, the TARGET switches to command phase for the

second command. The arbitration and selection phases are eliminated for the

2-15

CUSTOM SCSI PACKETS

second command. The following linked command example may be

performed on the Archive 2150 disk controller (it supports linked commands).

The SCSI firmware does not support linked command with flag.

PACKET FOR THE LINKED COMMAND EXAMPLE:

PACKET

DS.W 1

DC.L LSCRIPT SCRIPT POINTER

DC.W $0400

RETURNED STATUS WORD (BYTES 0 AND 1)+2

CONTROLLER LEVEL=4, DEVICE LUN=0

DC.L CT1

DC.W 0

COMMAND TABLE POINTER

RESERVED +C

INITIATOR ROLE CUSTOM SEQUENCE

RESERVED

+10

+12

DC.W $001C FUNCTION CODE=CUSTOM SCSI SEQUENCE +14

DC.W $0260

DS.W 1

DC.W 3

INTERRUPT LEVEL 2, VECTOR $60

+16

STATUS BYTES 2 AND 3

RETRY COUNT=3

+18

+1A

SCRIPT for a READ followed by a WRITE:

LSCRIPT DC.B $14 MESSAGE OUT (IDENTIFY)

DC.B $04 COMMAND (READ)

DC.B $0C DATA IN

DC.B $10 STATUS

DC.B $18 MESSAGE IN

DC.B $04 COMMAND (WRITE)

DC.B $08 DATA OUT

DC.B $10 STATUS

DC.B $18 MESSAGE IN

DC.B $00 END OF SCRIPT

(LINKED COMMANDS REQUIRE AS MANY COMMAND TABLES AS

THERE ARE PIECES OF THE

LINKED COMMAND. I.E. FOR A READ/ WRITE LINKED COMMAND, 2

TABLES ARE REQUIRED)

2-16

Initiator Role Custom Packet

*****************************COMMAND TABLE FOR THE FIRST

COMMAND**************

CT1

DC.B %11000000

LINK FLAG ON

PARITY CHECKING ENABLED

DMA ENABLED

CUSTOM SEQ. FLAG=> FIRMWARE CHECKS STATUS

FIRMWARE USES SCSI RULES (RESELECT, ETC.)

RESERVED

X NO SCATTER/ GATHER OPERATION

X ASYNC SCSI TRANSFER

DC.B 0

RETRY COUNT=0

DC.L CT2

DC.W 6

THE ADDRESS OF THE SECOND COMMAND TABLE

COMMAND LENGTH = 6 (GROUP 0 COMMAND)

READ COMMAND

LUN=0, BLOCK ADDR MSB=0

BLOCK ADDR

(FULL BLOCK ADDR=$00086)

4 BLOCKS REQUESTED

CONTROL BYTE: FLAG BIT=1, LINK BIT=1.

DC.B $08

DC.B $00

DC.B $86

DC.B $04

DC.B $03

* see *NOTE below the second command table.

DC.B 00

DS.B 01

DC.B 07

DC.L $400

DC.L BUFF

DC.W 1

DON’T CARE

USER’S STATUS BYTE IS STORED HERE

SCSI INITIATOR ADDRESS = $07

4 BLOCKS * $100 BYTES/ BLOCK= $400 BYTES

DATA BUFFER ADDRESS

MESSAGE IN AREA ALLOCATION= 1 BYTE

DC.L MSIN1 MESSAGE IN AREA POINTER

DC.W 1

MESSAGE OUT AREA ALLOCATION = 1 BYTE

DC.L MSOUT1 MESSAGE OUT AREA POINTER

DS.B 342

REMAINING OF THE 384 BYTE COMMAND TABLE

MSIN1

MSOUT1

DS.B 1

DC.B $C0

MESSAGE IN AREA FOR COMMAND TABLE #1

THE IDENTIFY MESSAGE FOR LUN 0, WITH

RESELECTION

BUFF DS.B $400

4 BLOCK DATA BUFFER

2-17

CUSTOM SCSI PACKETS

*****************************COMMAND TABLE FOR THE WRITE

COMMAND**************

CT2

DC.B %01000000

LINK FLAG OFF

PARITY CHECKING ENABLED

DMA ENABLED

CUSTOM SEQ. FLAG=> FIRMWARE CHECKS STATUS

FIRMWARE USES SCSI RULES (RESELECT, ETC.)

RESERVED.

X NO SCATTER/ GATHER

X ASYNC SCSI TRANSFER

DC.B 0

RETRY COUNT=0

DC.L 0

NO LINK ADDRESS PROVIDED.

COMMAND LENGTH = 6 (GROUP 0 COMMAND)

WRITE COMMAND

LUN=0, BLOCK ADDR MSB=0

BLOCK ADDR

(FULL BLOCK ADDR=$00086)

4 BLOCKS REQUESTED

CONTROL BYTE: FLAG BIT=0, LINK BIT=0.

DON’T CARE

DC.W 6

DC.B $0A

DC.B $00

DC.B $86

DC.B $04

DC.B $00

DC.B 00

DS.B 01

DON’T CARE

USER’S STATUS BYTE IS STORED HERE

SCSI INITIATOR ADDRESS = $07

4 BLOCKS * $100 BYTES/ BLOCK= $400 BYTES

DATA BUFFER ADDRESS

MESSAGE IN AREA ALLOCATION= 1 BYTE

DC.B 07

DC.L $400

DC.L BUFF

DC.W 1

DC.L MSIN2 MESSAGE IN AREA POINTER

DC.W 1

MESSAGE OUT AREA ALLOCATION = 1 BYTE

DC.L MSOUT2 MESSAGE OUT AREA POINTER

DS.B 342

REMAINING OF THE 384 BYTE COMMAND TABLE

MSIN2

MSOUT2

DS.B 1

DC.B $00

MESSAGE IN AREA FOR COMMAND TABLE #1

NO MESSAGE OUT PHASE FOR THE SECOND

COMMAND.

2-18

TARGET Enable Custom Packet

A linked command with the flag bit set is not supported,

and the flag bit is ignored if it is set.

Note

TARGET Enable Custom Packet

The TARGET enable custom packet is shown in the following table.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Not Used

Command Table Pointer (MSW) (Note 2)

Command Table Pointer (LSW) (Note 2)

Flag = C

Function Code (1C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Retry Count

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

2-19

CUSTOM SCSI PACKETS

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

xxxxxxxx

Not used

Command table

pointer (MSW) (Note

$0A

xxxxxxxx

00000000

Command table

pointer (LSW) (Note

$0C

$0E

00000000

1.......

.1......

..000000

00000000

xxxxxxxx

Reserved

TARGET role

TARGET enable

Reserved

$0F

$10

$12

$14

$15

Reserved

00000000

Reserved

SCSI function ($1C =

Custom SCSI

sequence)

$16

$17

00000xxx

xxxxxxxx

Interrupt level (7 to 1)

Vector number to use

upon return

$18

$19

xxxxxxxx

Status from SCSI

firmware (byte 2)

(Note 1)

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

00000000

Reserved

Retry count must be 0

Refer to Chapter 3.

NOTES:

Command table = 384 bytes

RAM work area.

2-20

TARGET Enable Custom Packet

This second "class" of custom packets is used to enable TARGET role service

by the MVME147 SCSI firmware. All eight SCSI-defined logical units can be

independently serviced through the firmware. Each logical unit needs to be

enabled separately. In other words, a TARGET enable packet is sent for each

logical unit that you want to service. The TARGET enable packet should not

be deallocated even after TARGET is enabled and command is received (final

return for TARGET enable). It is recommended that you use the same packet

for TARGET enable and TARGET sequence. The last packet should be saved

until the next TARGET command is received.

Packet description:

WORD $00:

CONTROLLER LUN -- This is the target SCSI address of the

MVME147. Because target firmware already knows the SCSI

address this field is used to compare with the known target

SCSI address. If the address does not match, an ID error is

reported when the packet is received.

DEVICE LUN -- This number (0 through 7) specifies which

TARGET logical unit is to be enabled. All eight may be

enabled, but only one is enabled per TARGET enable call.

WORD $02:

STATUS bytes 0 and 1 -- These status bytes are the codes

returned to you by the firmware. (For code definitions, refer

to Chapter 3.)

WORDS $04 and $06:

SCRIPT POINTER -- The script pointer is not used by the

firmware for the TARGET enable call.

WORDS $08 and $0A:

COMMAND TABLE POINTER -- This is the pointer to the

command table (384 bytes of RAM). Each TARGET logical

unit needs one command table. No sharing of command

tables is allowed among the enabled logical units. When a

TARGET command is complete, this command table must not

be deallocated because of future use. However, the command

table area could be used by subsequent TARGET commands.

WORD $0E=$C000:

This code classifies the custom packet as a TARGET enable

call to the firmware.

WORD $14:

The code of $1C classifies the packet as a custom packet.

2-21

CUSTOM SCSI PACKETS

WORD $16:

The interrupt level must be no-zero because TARGET role

support is not used in non-interrupt mode. (If TARGET role

support were done in polled mode, nothing else would be

able to run on the MVME147 other than the TARGET

firmware because the microprocessor would poll for a

selection as a TARGET.) The vector number is used to

provide the return path to you. (You take over that vector and

point it to your service routine.)

IMPLEMENTATION NOTE: It is highly recommended that

you assign a unique return vector for each enabled TARGET

logical unit in order to keep the service of each LUN separate

and independent from the other LUNs.

WORD $18:

WORD $1A:

Not used by the firmware for the TARGET enable call.

TARGET Sequence Custom Packet

The TARGET sequence custom packet is shown in the following table.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Script Pointer (MSW)

Script Pointer (LSW)

Command Table Pointer (MSW) (Note 2)

Command Table Pointer (LSW) (Note 2)

Flag = 8

Function Code (1C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

2-22

TARGET Sequence Custom Packet

Retry Count

+$1A

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

xxxxxxxx

Script pointer (MSW)

Script pointer (LSW)

xxxxxxxx

Command table

pointer (MSW) (Note

$0A

xxxxxxxx

00000000

Command table

pointer (LSW) (Note

$0C

$0E

00000000

1.......

.0......

..000000

00000000

xxxxxxxx

Reserved

TARGET role

TARGET sequence

Reserved

$0F

$10

$12

$14

$15

Reserved

00000000

Reserved

SCSI function ($1C =

custom SCSI

sequence)

$16

$17

00000xxx

xxxxxxxx

Interrupt level (7 to 1)

Vector number to use

upon return

$18

xxxxxxxx

Status from SCSI

firmware (byte 2)

(Note 1)

2-23

CUSTOM SCSI PACKETS

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

00000000

0000xxxx

Reserved

Retry count must be 0

Refer to Chapter 3.

NOTES:

Command Table = 384 bytes

RAM work area.

This third "class" of custom packets is used to service received commands and

messages for an enabled MVME147 TARGET logical unit. When an initiator

selects the MVME147 as a TARGET, the firmware switches to TARGET role,

determines which logical unit is desired by the initiator, and returns to the

TARGET service routine (through the vector supplied in the TARGET enable

packet) for user service of the initiator request. If the initiator that selected the

MVME147 as a TARGET does not send an illegal message, the TARGET role

firmware sequences the SCSI bus to the command phase, read in a CDB, store

the CDB in the command table provided through the TARGET enable packet,

and return through the vector provided for the selected logical unit for

command service. If the command was received, a final status of $xx17 or an

intermediate status of $xx06 is stored in the status word of the particular LUN

packet. The final status code of $xx17 is returned if an IDENTIFY WITH

RESELECTION message was received. The intermediate status code of $xx06

is returned if ATN* was not asserted during selection or if an IDENTIFY

WITHOUT RESELECTION message was received. You then use a TARGET

sequence packet to service the command.

IMPLEMENTATION NOTE: The SCSI firmware DOES provide information

to you as to which SCSI initiator is requesting service from the TARGET in

command table byte offset $15.

Packet description:

WORD $00:

CONTROLLER LUN -- This binary number must match the

SCSI level of the MVME147 as in Target Enable Custom

Packet.

DEVICE LUN -- This number identifies the particular logical

unit to service an initiator request.

WORD $02:

STATUS bytes 0 and 1 -- This is the firmware status word that

tells you how your packet was serviced (finished, error, etc.).

2-24

TARGET Sequence Custom Packet

WORDS $04 and $06:

SCRIPT POINTER -- The address of the TARGET script to be

performed to service the initiator request.

In TARGET role, the MVME147 controls the SCSI bus. The

TARGET script tells the firmware which information transfer

phases to cycle through to service the initiator request that

was encoded in the CDB.

In TARGET role, the names of the information transfer

Note

phases are consistent with initiator role.

By SCSI

definition, transfer direction is always referenced to the

initiator. That is, the message in phase is a message transfer

INTO the initiator. For TARGET role the message-in phase

is still INTO the initiator (notice it is OUT of the TARGET).

TARGET scripts to service commands do not include

command phases. Below are examples of TARGET scripts for

two CDBs; one is a receive CDB and the other is a send CDB.

Example 1: Receive (peripheral device type = processor

devices)

CDB byte 0: $08

CDB byte 1: $20

CDB byte 2: $00

CDB byte 3: $04

CDB byte 4: $00

CDB byte 5: $00

Command is a receive

The desired LUN is 1

Allocation length MSB

Allocation length

Allocation length LSB

Control byte=0: no link, no flag

Target script for example 1:

DC.B $0C

DC.B $10

DC.B $18

DC.B $1C

DATA-IN PHASE

STATUS PHASE

MESSAGE-IN PHASE

END OF TARGET SCRIPT

The command table contains the information required to

carry out the bus phase. For example, the data pointer tells

the firmware where the buffers are located in MVME147-

accessible memory.

1. During the data-in phase, the $400 bytes are sent to the initiator.

2. During the status phase, the GOOD status is sent to the initiator.

2-25

CUSTOM SCSI PACKETS

3. During the message-in phase, the COMMAND COMPLETE message is

sent to the initiator.

4. The END OF TARGET SCRIPT code causes the firmware to disconnect

from the bus and return to you (through the vector provided in the

TARGET sequence packet) with a final status of $xx18, indicating the

TARGET script was completed successfully.

Example 2: Send (peripheral device type = processor devices):

CDB byte 0: $0A

CDB byte 1: $20

CDB byte 2: $00

CDB byte 3: $03

CDB byte 4: $00

CDB byte 5: $00

Command is a write

The desired LUN is 1

Allocation length MSB

Allocation length

Allocation length LSB

Control byte=0: no link, no flag

Target script for example 2:

DC.B $08

DC.B $10

DC.B $18

DC.B $1C

DATA OUT PHASE

STATUS PHASE

MESSAGE IN PHASE

END OF TARGET SCRIPT

1. During the data-out phase, the initiator writes data to the MVME147. The

byte count is $300.

2. During the status phase, the GOOD status is sent.

3. During the message-in phase, the COMMAND COMPLETE message is

sent.

4. The end of TARGET script code causes the firmware to disconnect from

the SCSI bus and return to you through the vector provided in the

TARGET sequence packet.

WORDS $08 and $0A:

COMMAND TABLE POINTER -- The address of the

TARGET role command table. Below is a description of the

requirements of the TARGET command table.

TARGET COMMAND TABLE DESCRIPTION:

CT word 00: (Byte 0 -- status/ flag byte.)

Bit assignments:

2-26

TARGET Sequence Custom Packet

D7 = Not used by the TARGET role firmware. (This is the link bit.

Command linking is not accomplished with the use of this

bit.)

D6 = Not used by the TARGET role firmware. (This is the parity

bit. )

D5 = Not used by the TARGET role firmware. (This is the DMA

disables bit. DMA is used in TARGET role: 0 = DMA, 1 = no

DMA)

D4 = MUST be zero. Not used by the TARGET role firmware. (This

is the interpret bit and only relevant for initiator role.)

D3 = Not used by the TARGET role firmware. (This is the

SASI/ SCSI rule bit. The TARGET role module determines

which rule to follow by the initiator assertion of ATN and the

re-select option bit of the IDENTIFY message.)

D2 = This is a scatter/ gather bit. If DMA is enabled, the data

pointer in the command table could be used to point to the

scatter/ gather table if this bit is 1.

D1 = 1 = SYNC transfer enable.

0 =ASYNC transfer enable.

D0 = Reserved.

(Byte 01): Not used by the TARGET role firmware. Must be set to $00.

CT words $02 and $04: LINK POINTER. Not used by the TARGET role

firmware.

CT word $06: COMMAND LENGTH. Not used by the TARGET sequence call.

(The CDB received from initiator is stored in the command table that was

provided in the TARGET enable call. You may use the same command tables

for the enable and sequence calls to interpret receive CDB, but the TARGET

sequence call does not make use of the command length and of the CDB itself.)

CT words $08 through $12: COMMAND DESCRIPTOR BLOCK. Not used by

the TARGET sequence call. (Refer to CT word 06 above for command length.)

CT word $14, even byte: User SCSI STATUS. For a TARGET sequence, you can

set the vendor unique bits in the status byte. The MVME147 SCSI firmware

sends the contents of this byte ORed with the firmware SCSI status byte in

offset $64 if a status phase code is encountered in the TARGET script. (Odd

byte $15: initiator SCSI address which is interfacing with the TARGET role

firmware.)

2-27

CUSTOM SCSI PACKETS

CT words $16 and $18: DATA LENGTH. The number of bytes to transfer

during either the data-in or the data-out phase. Not used if DMA is enabled

and SG bit is set in status/ flag byte in word o.

CT words $1A and $1C: DATA POINTER. If a DATA-IN code is in the

TARGET script, the firmware starts transferring data FROM the contiguous

data buffer pointed to by this pointer. If a DATA-OUT code is in the TARGET

script, the firmware starts transferring data TO the contiguous data buffer

pointed to by this pointer. This pointer points to SG table if DMA SG is used.

CT word $1E: MESSAGE-IN LENGTH. Not used by the TARGET role

firmware for the message byte count in the message-in phase.

CT words $20 and $22: MESSAGE-IN POINTER. If a message-in code is in the

TARGET script, the firmware sends the messages from message-in buffer

where this pointer points.

CT word $24: MESSAGE-OUT LENGTH. Not used by the TARGET role

firmware.

CT words $26 and $28: MESSAGE-OUT POINTER. If the initiator that is

threaded to the MVME147 sends an extended message to the MVME147, the

firmware stores it in the message buffer that is pointed to by this pointer. (The

ATN condition is only serviced if the ATN signal is asserted during selection

or certain phases. The initial IDENTIFY message is handled internally by the

firmware for threading purposes. If the ATN condition arises during a phase

that can be serviced, the message that is received from the initiator is stored in

the buffer pointed to by this message-out pointer.)

CT word $64, even byte : TARGET role firmware SCSI status byte set by

firmware during target sequence packet execution..

The remaining bytes of the command table are reserved.

Packet word $0E=$8000:

This word classifies the custom SCSI packet as a TARGET sequence.

Packet word $14=$001C:

This word classifies the packet as a custom SCSI sequence.

Packet word $16:

The interrupt level must be non-zero because TARGET role is only supported

for interrupt mode. The vector number provides the return path for the

firmware to you.

Packet word $18:

2-28

TARGET Sequence Custom Packet

STATUS BYTES 2 and 3. Not used by the TARGET role firmware.

Packet word $1A:

RETRY COUNT. Not used by the TARGET role firmware.

2-29

CUSTOM SCSI PACKETS

2-30

PACKET RETURN STATUS

Packet Return Status

When packets are returned to the user, they contain two status words: one

with an offset of $02 and the other with an offset of $18, as shown in the tables

below, respectively. The first table details the status codes contained in the

word at offset $02. Refer to the Interface Rules for the SCSI Firmware section in

Chapter 5 for additional information. Also, refer to the command table

returned fields.

Status word offset $02

1508 0700

Status Code (Refer to Table 3-1)

Control Flags

Bits 12-8 (reserved)

Bit 13 (RTE FLAG) (of interest only to the

programmer)

1 = This return was not preceded by an

interrupt and is the first return since

command entry. In this case, no RTE is

required.

0 = This return was preceded by an interrupt

and is not the first return, therefore,

an RTE is required to continue proces-

sing from where an interrupt occurred.

save area (D0-D7, A0-A6).

Bit 14 (ADDITIONAL STATUS)

1 = External status is valid.

0 = External status is not valid.

PACKET RETURN STATUS

Bit 15 (FINALSTAT)

1 = Intermediate return.

0 = Final status.

The script processing completed succ-

essfully, OR the script processing

encountered a fatal error.

This does not mean that the operation that the

user requested on the SCSI was successful. The

status is contained in the status code (bits 7-0.)

Note

*(L1

*(L2

*(L3

*(L4

Status word offset $18

1512 1108 0704 0300

Request Sense

SCSI

Phase

Reserved

Flags

Status

(0 if not used)

Bit 0

(RES)

Re-

served)

Bit 1

(ILI)

Incorrect

length

indicator.

3-2

Packet Return Status

Bit 2 (EOM)

End of

media.

Bit 3 (FM)

Filemark

Bit 4 (COMMAND

RETRY)

1 = Retries were

performed.

Bit 5 (COMMAND RE-

TRY OVERFLOW)

1 = Retry overflow.

The command

was retried

"retry count"

times.

Bits 6 and 7 (reserved)

*(L1

*(L2

*(L3

*(L4

*(L5

*(L6

*(L7

Return Status Packet

Even Byte \

Odd Byte \

3-3

PACKET RETURN STATUS

+$00

+$60

+$62

Block Number in Error (MSW)

Block Number in Error (LSW)

+$64

+$66

+$68

+$6A

+$6C

+$6E

+$70

+$72

+$74

SCSI Controller Status

Transfer Address

Command

Offset

Sense Data Block

+$9E

$60

Sense Data Block

xxxxxxxx

Block number in error

(MSW) -- This is the

returned information

bytes taken from

bytes

3-6 following an error

from a SCSI device

and a request sense

command.

$62

$64

xxxxxxxx

Block number in error

(LSW)

Status byte from SCSI

controller

(unchanged)

$65

$66

xxxxxxxx

Reserved

Transfer address -- for

a read or write.

3-4

Packet Return Status

This is the memory

address of the next

byte

to be transferred.

$68

xxxxxxxx

Transfer address -- for

a read or write.

$72

Command error

status byte (valid

following

a command error

$0B)

$73

$74

xxxxxxxx

Offset within packet.

Sense data block

xxxxxxxx

$9E

xxxxxxxx

Sense data block

Table 3-1. Packet Status Codes

CODE

MEANING

NOTES

Intermediate Return

Codes

$02

Wait for interrupt; command

door open. OK to send new

commands for other devices

to firmware.

$04

$06

A message has been received.

You must interpret.

(TARGET mode) received a

command from initiator, no

disconnect allowed.

$08

(TARGET mode) data

received from initiator, user

must interpret then continue

with new t_seq.

1,9

3-5

PACKET RETURN STATUS

Table 3-1. Packet Status Codes

MEANING

NOTES

CODE

Intermediate Return

Codes

$09

(TARGET mode) data

received from initiator with

parity error, user must

interpret then continue with

new t_seq.

1,9

Final Return Codes

$00

GOOD. Script processing is

OK.

$01

$02

Undefined problem.

TARGET has Received Data

without error, and user may

interpret then continue with

new t_seq.

$03

Interrupt handler was

entered with no pending IRQ

($F00050).

$04

$05

Reselection not expected

from this TARGET.

TARGET thinks it is working

on linked commands but the

command table does not.

$06

Linked command has error

status code; command has

been aborted.

$07

$08

Received an illegal message.

The message we have tried to

send was rejected.

$09

TARGET Encountered a

parity error in data

transfer(in) phase and user

must interpret then continue

with new t_seq.

3-6

Packet Return Status

Table 3-2. Packet Status Codes (cont’d)

CODE

MEANING

NOTES

$0A

SCSI bus reset received (A1 pointing to packet list). (Refer to the

SCSI Bus Reset Packet section in Chapter 7.)

$0B

Command error (bad command code, bad timing, or command

door was closed when a command was received) = 00. Custom

SCSI sequence: controller level not equal to "147 local level", or

interrupt not on. Format: format with defects on a con- troller type

not supported. Controller reset: controller not SCSI type. Space

(tape): undefined mode. Mode select (tape): undefined controller

type. Mode sense (tape): undefined controller type.

$0C

$0D

$0E

Size error (invalid format code).

Bad ID in packet or local ID.

Error in attach (not previously attached, bad device LUN,

unsupported controller).

$0F

$10

Busy error (device has a command pending).

There is disagreement between initiator and TARGET regarding

the number of bytes that are to be transferred.

$11

$12

$13

$14

Received a BERR* while in DMA mode.

Selection time-out. TARGET does not respond.

SCSI protocol violation. Controller reset: controller not SCSI.

Script mismatch. CHECK STATUS. If SCSI status within

command table (offset $14 for initiator role) is zero, then assume

script mismatch, otherwise use SCSI packet status.

$15

Script mismatch. The TARGET sequence of operation did not

match the script.

$16

$17

$18

$19

Illegal SCSI state machine transition.

Command has been received (TARGET role). Disconnect allowed.

Script complete in TARGET role.

Script complete and new command loaded (TARGET role linked

command).

$1A

TARGET module called. TARGET role not supported.

3-7

PACKET RETURN STATUS

Table 3-3. Packet Status Codes (cont’d)

CODE

MEANING

NOTES

$1B

TARGET module rejected an initiator message and returned with

this status to a particular LUN service routine.

$1C

$1D

TARGET module sent a check status with an "illegal request" sense

block to some initiator because the particular LUN that the

initiator wanted was not enabled.

TARGET module sent a busy status to the calling initiator because

the particular LUN that the initiator wanted was already busy

servicing a command.

$1E

$1F

TARGET received ABORT message from the SCSI initiator.

TARGET received DEVICE RESET message from the SCSI

initiator.

Request-Sense-Data Error-Class 7 Codes

(Controller-Dependent)

$20

$21

NO SENSE. Indicates that there is no specific sense key

information to be reported for the designated logical unit.

2,3

RECOVERED ERROR. Indicates that the last command

completed successfully with some recovery action performed by

the TARGET. Details can be determined by examining the

additional sense bytes and information bytes.

$22

$23

$24

NOT READY. Indicates that the logical unit addressed cannot be

accessed. Operator intervention may be required to correct this

condition.

2,3

MEDIUM ERROR. Indicates that the TARGET detected a

nonrecoverable error condition that was probably caused by a flaw

in the medium or an error in recording data.

HARDWARE ERROR. Indicates that the TARGET detected a

nonrecoverable hardware failure (for example, controller failure,

device failure, parity error, etc.) while performing the command or

during self test.

$25

ILLEGAL REQUEST. Indicates that there was an illegal parameter

in the command descriptor block or in the additional parameters

supplied as data.

2,3

3-8

Packet Return Status

Table 3-4. Packet Status Codes (cont’d)

CODE

MEANING

NOTES

$26

UNIT ATTENTION. Indicates that the removable media may

have been changed or the TARGET has been reset.

2,3

$27

$28

DATA PROTECT. Indicates that a command that reads or writes

the medium was attempted on a block that is protected from this

operation.

2,3

BLANK CHECK. Indicates that a write-once read-multiple device

or a sequential access device encountered a blank block while

reading or a write-once read-multiple device encountered a

nonblank block while writing.

2,3

$29

$2A

$2B

VENDOR UNIQUE. Used for reporting vendor unique conditions

(for Saber AP = format complete).

2,3

COPY ABORTED. Indicates that a copy or a copy and verify

command was aborted due to an error condition.

ABORTED COMMAND. Indicates that the TARGET aborted the

command. The initiator may be able to recover by trying the

command again.

$2C

$2D

EQUAL. Indicates a search data command has satisfied an equal

comparison.

2,3

VOLUME OVERFLOW. Indicates that a buffered peripheral

device has reached an end-of-medium and data remains in the

buffer that has not been written to the medium. A recover

buffered data command may be issued to read the unwritten data

from the buffer.

$2E

$2F

MISCOMPARE. Indicates that the source data did not match the

data read from the medium.

2,3

RESERVED. This sense key is reserved.

SCSI Status Returned in Status Phase

SCSI status = $02. CHECK.

$31

$32

$34

$38

$3A

$3C

2,4

SCSI status = $04. CONDITION MET.

SCSI status = $08. BUSY.

SCSI status = $10. INTERMEDIATE/ GOOD.

SCSI status = $14. INTERMEDIATE/ CONDITION MET/ GOOD.

SCSI status = $18. RESERVATION CONFLICT.

3-9

PACKET RETURN STATUS

Table 3-5. Packet Status Codes (cont’d)

CODE

MEANING

NOTES

Request-Sense-Data Error-Class 0 through 6 Codes

(Controller-Dependent)

$40

$41

$42

$43

$44

$45

$46

$47

$49

$4D

$50

$51

$52

$53

$54

$55

$57

$58

$59

$5A

$5C

$5E

$5F

$60

$61

$62

$63

NO ERROR STATUS.

2,5,6

2,5,7

2,5,8

NO INDEX SIGNAL.

NO SEEK COMPLETE.

WRITE FAULT.

DRIVE NOT READY.

DRIVE NOT SELECTED.

NO TRACK 00.

MULTIPLE DRIVES SELECTED.

CARTRIDGE CHANGED.

SEEK IN PROGRESS.

ID ERROR. ECC error in the data field.

DATA ERROR. Uncorrectable data error during a read.

ID ADDRESS MARK NOT FOUND.

DATA ADDRESS MARK NOT FOUND.

SECTOR NUMBER NOT FOUND.

SEEK ERROR.

WRITE PROTECTED.

CORRECTABLE DATA FIELD ERROR.

BAD BLOCK FOUND.

FORMAT ERROR. (Check track command.

UNABLE TO READ ALTERNATE TRACK ADDRESS.

ATTEMPTED TO DIRECTLY ACCESS AN ALTERNATE TRACK.

SEQUENCER TIME OUT DURING TRANSFER.

INVALID COMMAND.

ILLEGAL DISK ADDRESS.

ILLEGAL FUNCTION.

VOLUME OVERFLOW.

3-10

Packet Return Status

1. Intermediate return codes. Bit 15-1, actual word=$80xx, $90xx, etc.

TES

2. Final return codes.

3. Sense key status codes for Request-Sense-Data error -- class 7. An offset of $20 is

added to all sense key codes.

4. The SCSI status sent from the controller is ANDed with $1E, shifted right one

bit, and $30 added.

5. Sense key status codes for Request-Sense-Data error -- classes 0-6. An offset of

$40 is added to all sense key codes.

6. Drive error codes.

7. Controller error codes.

8. Command errors.

9. Intermediate return codes, the no disconnection is allowed according to the

script.

3-11

PACKET RETURN STATUS

3-12

SCSI FIRMWARE

INTERRUPT STRUCTURE

SCSI Firmware Interrupt Structure

The SCSI interface firmware was designed for processor efficiency. Whenever

the SCSI bus is in a state that does not need monitoring, the firmware releases

the processor so it may perform other functions such as user tasks and lower

priority events. In these cases, an interrupt brings processor control back to

the firmware.

A return vector is provided to the SCSI firmware in all cases through the

packet pointed to by register A2. Whenever the firmware returns to the user

through this return vector, it flags whether the processor was brought back to

the firmware through an external interrupt. This flagging is done by the RTE

FLAG bit in the status word stored in the user packet. If the bit = 1, no RTE is

to be performed by the user. If the bit = 0, eventually an RTE is required by the

user to return the processor to the interrupted task.

Similarly, whenever the RTE instruction is to be executed, the user must

restore the registers before executing the RTE. This restoration of registers is

mandatory to properly restore the task that was interrupted. Upon a return

through the user vector, address register A3 contains an address of a save area

where the registers were saved. If A3 = 0, then no registers were saved (that

is, no interrupt was taken and the RTE FLAG bit should be a 1).

Processor control is returned to the user in a variety of ways:

Intermediate status:

$02 Wait for interrupt (open)

$04 Message received

$06 Command received (TARGET role)

or Final status.

Refer to the Interface Rules for a Single Caller section in Chapter 5 for details.

For the intermediate statuses, control is given back to the firmware in two

ways. One is through an WD33C93 interrupt (WAIT FOR INTERRUPT

(OPEN)). The other return mechanism is through a direct branch or jump into

SCSI FIRMWARE INTERRUPT STRUCTURE

the REACTIVATION entry point of the SCSI firmware. The WAIT FOR

INTERRUPT (OPEN) status is usually given when a particular TARGET is

"threaded" to the MVME147 on the SCSI bus, and is slow in transitioning

between information transfer phases. A bus phase interrupt brings the

processor back to the SCSI firmware to finish the command execution that was

temporarily slowed down by the TARGET.

For the WAIT FOR INTERRUPT (OPEN) status, the user may send a new

command because the SCSI bus is free.

The second method of returning control involves the direct branch or jump to

the REACTIVATION entry point of the firmware. For all the statuses involved

(WAIT TIME, MESSAGE RECEIVED, COMMAND RECEIVED), the

MVME147 is the current SCSI bus initiator and the user may only service the

current "thread".

The SCSI firmware was designed to operate in both interrupt and non-

interrupt modes. When the user chooses the interrupt mode of operation, the

WD33C93 interrupt is enabled at the level specified in command packet in the

MVME147 interrupt handler. Vector number $45 is used by the WD33C93 for

the SCSI bus interrupts and the SCSI firmware initializes vector offset $114 to

point to the SCSI firmware interrupt handler.

Whenever processor control is passed to the SCSI firmware interrupt handler,

the MC68030 interrupt mask must be at a level no lower than that specified in

the command packet. As processor control is switched out of the interrupt

handler, the MC68030 interrupt mask is still at the same level.

4-2

WRITING A DRIVER

Introduction

This chapter covers information essential in writing a driver to support the

SCSI interface in interrupt mode. A driver for non-interrupt mode is a trivial

subset of the interrupt mode driver. The approach taken is to describe the

major sections of a driver that need to be written. The examples shown have

been extracted from the VERSAdos SCSI driver, and are dependent on the

driver interface to the VERSAdos operating system. For this interface, see

Figure 5-1. For details of the interaction between the driver and the SCSI

firmware, see Figure 5-2.

Any driver that communicates to the SCSI firmware starts by building (for

single callers) a command packet in memory and calling the command entry

point SCSI_CMD in the MVME147Bug. The address of the packet is

contained in register A2.

Access to the six SCSI entry points is provided through the use of a jump table

located within the beginning of the MVME147 debug monitor. The jump table

entry points and their SCSI firmware functions are shown in the following list.

EQU

$FFFE077C

$FFFE0782

SCSI command entry.

SCSI_CMD

SCSI_ACTV

SCSI command

reactivation entry.

EQU

$FFFE0788

$FFFE078E

SCSI interrupt entry.

SCSI_INT

SCSI_FUN

FUNNEL command

entry.

EQU

$FFFE0794

$FFFE079A

Come-again entry.

RTE entry.

SCSI_CA

SCSI_RTE

Interrupts from the SCSI controller chip are through vector $45 (offset $114).

Interrupts from the MVME147 SCSI DMA channel are through vector $46

(offset $118). The self interrupts from the MVME147 SCSI firmware use the

vector $4B (offset $12C) to return control to SCSI firmware. The SCSI firmware

sets these vectors to point to its interrupt entry point.

WRITING A DRIVER

Return from the SCSI firmware to the driver is done through the vector

supplied in the packet. The VERSAdos driver uses vector $4E (offset $138),

and tape driver uses vector $4D (offset $134). These vectors must be initialized

to point to a driver routine which handles the return. Refer to the Interface

Rules for the SCSI Firmware section in this chapter for details on the return.

The SCSI firmware can accept six commands (average) per peripheral device.

A busy error may be returned if too many commands are received for a device

depending on the firmware current activities. Until one command has been

completed, or abnormally terminated, no other command may be dispatched

to the firmware. Commands to any other device may be issued after a "wait

for interrupt (open)" ($02) intermediate status, or final status is returned from

the SCSI firmware to the driver. For more information, refer to the Interface

Rules for the SCSI Firmware section in this chapter.

Figure 5-1. SCSI Disk Driver Interface to VERSAdos

Figure 5-2. SCSI Disk Driver

Building the Packet

Chapter 2 provides the details necessary to build the command packet. After

the packet has been built, it needs to be passed to the SCSI firmware.

Passing Commands to the SCSI Firmware

Passing control from the driver to the SCSI firmware can be done by jumping

directly to the firmware from the driver. The return from the firmware back

to the driver is through the vector supplied within the packet. Because the

SCSI firmware can only accept six commands (average) for each device, you

may need to do internal queuing if more commands need to be sent to a

particular device.

Interface Rules for the SCSI Firmware

SCSI firmware may be called by single or multiple callers.

A single caller to the SCSI firmware is a driver or a server that provides a

single return path from the firmware. In other words, a single SCSI return

routine handles the status codes that the firmware passes. This definition does

not imply that only one return routine is used for interpreting status

5-2

Interface Rules for the SCSI Firmware

information; it does imply that only one routine handles the exit conditions

dictated by bit 13 of the second word in the user packet (also known as the

status word).

Multiple callers of the SCSI firmware are separate, independent drivers that

handle SCSI returns without knowledge of other drivers/ callers. This

definition implies that more than one routine handles the exit conditions

dictated by bit 13 of the first returned status word.

Interface Rules for Multiple Callers

Rule 1:

COMMANDS ARE SENT TO FUNNEL

COMMAND ENTRY.

You send a command by loading the address of your packet in address register

A2 and jumping to the FUNNEL command entry ($FFFE078E). The system

must be in supervisory mode and the interrupt mask must the equal specified

in the packet.

A command may be sent to the FUNNEL command entry almost any time,

except as noted below.

A command may not be sent to the FUNNEL command entry point after the

following returned intermediate status codes have been received (all

intermediate status codes have bit 15 set):

1. ($xx04) Message received.

2. ($xx06) Command received (TARGET role)

The above intermediate status codes are returned when a TARGET is threaded

and on the SCSI bus. These cases require entry to the RTE entry to complete

the firmware-specified actions. Refer to Rule 2 below.

You may send a command to the FUNNEL command entry on all final status

returns except:

Final status with bit 13 clear, indicating that an RTE is to be executed. (In this

case, a new command may be sent by entering the firmware at the SCSI_RTE

entry, $FFFE079A. Register A3 must remain intact.)

IMPLEMENTATION NOTE: Your interface driver or interface server usually

has the command entry processing and command status processing

decoupled. In other words, commands are sent to the SCSI firmware as a

result of a subroutine call or as a result of a TRAP call to your driver or server.

5-3

WRITING A DRIVER

Command status processing is the result of a firmware return to the vector

specified in the command packet. If this decoupling exists, the command

entry execution can only occur if the processor is not tied up performing SCSI

firmware functions or performing command status functions. That is, for the

processor to execute the command entry functions, it cannot be at the same

time executing command status functions. At the time the command is passed

to the driver/ server, the command entry code may go ahead and send the

command to the firmware without hesitation.

Rule 2:

INTERMEDIATE RETURNS MUST

REENTER AT

REACTIVATION OR RTE ENTRY.

The following is a list of intermediate status return codes provided by the

firmware (intermediate status codes have bit 15 set):

$xx02:

The SCSI firmware returns this code if a disconnect occurred

on the bus or if firmware is waiting for SCSI controller chip to

interrupt. Again, no action is required for this status other

than servicing the RTE (13) bit.

$xx04:

A message was received by the firmware that was either

uninterpretable or was received in TARGET role. You are

responsible for the interpretation of extended messages in

initiator and TARGET roles. The MVME147 is still threaded

on the bus when this status is passed to the user. The user

routine is responsible for interpreting the message and for the

proper return point. If bit 13 of the returned status is set, the

return is to the reactivation entry ($FFFE0782), and if bit 13 of

the returned status is clear, the return is to the RTE entry

($FFFE079A) and register A3 must remain intact. For this

status, an RTE is only "remembered for the next exit". If the

RTE bit is 0 with this status, an RTE is required. If this

condition occurs, address register A3 is pointing to a register

list.

$xx06:

In TARGET role, a command has been received and the SCSI

firmware stored in the command table. The firmware returns

this intermediate status to alert you to service the command

and to return to either the reactivation entry ($FFFE0782) no

5-4

Interface Rules for the SCSI Firmware

RTE required, or the RTE entry ($FFFE079A) RTE required as

status code $xx04 above. This intermediate status only

happens when the TARGET role is enabled.

CAUTION

Care must be taken not to modify the contents of

Rule 3:

ALL FINAL RETURNS MUST EXIT (THE

DRIVER)

PROPERLY THROUGH RTE, COME-

AGAIN, OR

REACTIVATION.

All final status code returns use bits 15 through 13 of the status word in the

packet (second word of the user’s packet) to tell you about the condition of the

SCSI firmware and of the SCSI bus.

BIT 15:

FINAL=(0)/ INTERMEDIATE=(1) STATUS bit. For all final

status return codes, this bit is 0.

BIT 14:

ADDITIONAL STATUS bit. For all final status returns, if this

bit is 1, additional status may be found in the additional status

area (CT +$74). If this bit is 0, no additional status is provided.

BIT 13:

RTE bit. If this bit is a 0, an RTE is required to finish an

interrupt thread. When this bit is 0, A3 contains a pointer to a

were saved. If the RTE is to be executed, the registers in the

RTE is to be executed.

The return mechanism on the final status codes only involve bits 13 of the user

status word (packet word 2). You MUST follow the priority scheme below if

you wish to interface to the SCSI firmware successfully.

RETURN CODE:

5-5

WRITING A DRIVER

IF BIT 13 IS SET THEN

RETURN TO THE CALLER OF YOUR CODE THROUGH

1. AN RTS IF HE CALLED YOU WITH A BSR/JSR

2. AN RTE IF HE CALLED YOU WITH A TRAP THAT

REQUIRES AN RTE RETURN.

(command

thread)

ELSE: (bit 13 is clear)

1. RESTORE THE REGISTER SET POINTED TO BY A3.

2. SOMEHOW PERFORM THE RTE REQUIRED BY THE

(interrupt

FIRMWARE.

thread)

SOME OPERATING SYSTEMS HAVE A COMMON

HANDLER THAT PERFORMS ALL RETURNS FROM

INTERRUPT

DOES NOT

PROCESSING. IN THIS CASE, EXECUTE THE COMMON

INTERRUPT HANDLER TO PERFORM THE RTE. IF THE

PARTICULAR OPERATING SYSTEM OF THE USER

HAVE A COMMON INTERRUPT HANDLER, EXECUTE THE

RTE INSTRUCTION.

ENDIF.

END OF RETURN CODE.

As can be seen from the return algorithm, the preprocessed packet and the

packet queuing process is done through the software interrupt (vector $4B) set

by the firmware and is transparent from user tasks. Here are the reasons:

1. A preprocessed packet has already run through the firmware BLDPCKT

(build

command packet) module and is ready to communicate with the initiator

or TARGET

on the SCSI bus. The only reason that this command packet did not make

to the bus was that a selection or a reselection interrupt of the MVME147

beat

this packet to the bus. It is imperative that this packet run next.

2. A packet was sent to the FUNNEL entry for processing. Because the bus

and

device wait queue was occupied at the instant the packet arrived, the

5-6

Interface Rules for the SCSI Firmware

FUNNEL

module queued the

request and returned to you with a $A002 intermediate status code.

In order for this packet to resume processing, the firmware sets the

software

interrupt to reenter the interrupt entry point ($FFFE0788).

3. The RTE condition receives third priority because if an RTE instruction

was effectively executed before the command pending or before the

queued

commands were serviced, the command pending or the queued

commands would never

be serviced.

EXCEPTIONS TO THE RETURN ALGORITHM:

Rule 4.

THE SCSI FIRMWARE CAN ONLY

PROCESS SIX

COMMAND PACKETS, IN AVERAGE, PER

PERIPHERAL

DEVICE AT A TIME.

The firmware has a 64 entry funnel queue for all the devices (1 per device

in average).

An index of the SCSI peripheral devices exists in the firmware in order to

provide threading information for command overlap on the SCSI bus. This

index

is called the attach table. One entry per peripheral device provides pointers

to the user packets, and command tables. In each command table, there is a 4

entry private wait queue for each device (each one points to a command

packet).

When a peripheral device

is given a command packet, its respective entry in the attach table is marked

"busy". If you send a command packet for a peripheral device that is

marked "busy", a busy error is returned if both private wait queue and

FUNNEL

queue are full. You may not see this busy

5-7

WRITING A DRIVER

error because if a subsequent command is queued in the FUNNEL queue or

the

wait queue, no busy error is given.

In average, a device could have one packet in FUNNEL queue, four packets in

wait queue, and an active command in attach table.

INTERFACE RULE SUMMARY FOR SCSI FIRMWARE USERS WITH

MULTIPLE CALLERS:

A typical system with multiple callers may have the following interfaces:

1. Disk driver: Handles all requests for SCSI disks.

2. Tape driver: Handles all requests for SCSI tapes.

3. TARGET LUN 0 service handler: Services requests for SCSI device

level for the MVME147 as a TARGET and services logical unit 0 of the

MVME147

TARGET.

4. TARGET LUN 1 service handler: Services requests for logical unit 1

of the MVME147 TARGET.

5. TARGET LUN 2 service handler: Services requests for logical unit 2

of the MVME147 TARGET.

6. TARGET LUN 3 service handler: Services requests for logical unit 3

of the MVME147 TARGET.

7. TARGET LUN 4 service handler: Services requests for logical unit 4

of the MVME147 TARGET.

8. TARGET LUN 5 service handler: Services requests for logical unit 5

of the MVME147 TARGET.

5-8

Interface Rules for the SCSI Firmware

9. TARGET LUN 6 service handler: Services requests for logical unit 6

of the MVME147 TARGET.

10. TARGET LUN 7 service handler: Services requests for logical unit 7

of the MVME147 TARGET.

The summary below is intended to help users who have multiple callers to

the SCSI firmware.

1. INTERMEDIATE RETURNS:

xx02:

PERFORM AN RTE (HOWEVER REQUIRED) IF BIT 13 OF

THE

RETURNED STATUS WORD IS 0 OR RETURN TO THE

CALLER

OF THE DRIVER/ SERVER BY THE APPROPRIATE

METHOD.

E.G. IF THE DRIVER IS CALLED BY A BSR, AN RTS

SHOULD BE USED.

xx04:

AFTER APPROPRIATE PROCESS, RETURN TO THE

REACTIVATION

ENTRY ($FFFE0782) IF

BIT 13 OF THE RETURNED STATUS WORD IS 1, OR

RETURN

TO THE RTE ENTRY ($FFFE079A) IF BIT 13 OF THE

RETURNED STATUS WORD IS 0.

xx06:

SAME RULE AS FOR xx04 ABOVE.

xx08:

INITIATOR DATA RECEIVED, USER MUST INTERPRET

THEN CONTINUE WITH

NEW TARGET SEQUENCE PACKET BY FOLLOWING

SAME RULE AS FOR xx04 ABOVE.

5-9

WRITING A DRIVER

xx08:

SIMILAR TO xx08 ABOVE, ONLY THE DATA RECEIVED

HAS SOME PARITY ERROR

OCCURRED.

2. FINAL RETURNS:

STATUS WORD BIT 13:

(RTE)

IF CLEAR, SOMEHOW RESTORE

SET AND PERFORM AN RTE. IF SET,

THE FIRST RETURN FROM THE SCSI

FIRM-

WARE (COMMAND THREAD) AND THE

USER

SHOULD RETURN TO WHOMEVER

CALLED

THE DRIVER (RTS, ETC.).

SAMPLE RETURN CODE FOR ONE OF MANY CALLERS OF THE SCSI

FIRMWARE:

It may not be clear to the casual reader that address

an RTE is to be executed, address register A3 points

to the register save area. The subroutine

Note

RESTORE_REG uses register A3 to restore the

registers D0 through D7 and A0 through A6. If a reentry

to the RTE entry is executed, the address register A3

must remain intact.

(SCSI_RET: is the label that is pointed to by the vector provided in the

user packet.)

SCSI_RET:

5-10

Interface Rules for the SCSI Firmware

MOVE.W 2(A2),D0

BTST #15,D0

STATUS WORD TO D0.

FINAL/INTERMEDIATE STATUS?

BEQ FINALSTAT

IF 0, THE RETURN IS A FINAL ONE.

******************************************************************

************

*THE FOLLOWING CODE CHECKS ALL ALLOWED INTERMEDIATE RETURN CODES.

CMP.B #$02,D0

IF <EQ> THEN

WAITING FOR AN INTERRUPT? (BUS CLEAR)

BRA RET_OUT NO NEW COMMANDS TO SEND BECAUSE NO QUEUING

NECESSARY

* FOR MULTIPLE CALLERS, THE SCSI FIRMWARE QUEUES COMMANDS WHEN THE

BUS IS

* BUSY.

* BECAUSE OF THIS REASON, NO COMMAND QUEUING IS NECESSARY IN THE

DRIVER. IF

* THERE IS NO QUEUING IN THE DRIVER, THE DRIVER WILL NOT HAVE A NEW

COMMAND

* TO SEND WHENEVER AN INTERMEDIATE OR FINAL RETURN OCCURS. THE

COMMANDS ARE

* ALWAYS SENT AS THEY ARRIVE TO THE DRIVER.

* ’RET_INT’ is the user’s code to handle the return from interrupt

process.

ENDI

CMP.B #$04,D0

IF <EQ> THEN

BSR INTERPRET

MESSAGE INTERPRETATION?

INTERPRET IS A MESSAGE INTERPRETATION

ROUTINE

BRA RET_INT

ENDI

CMP.B #$06,D0

IF <EQ> THEN

BSR SERVCMD

COMMAND RECEIVED FOR THE TARGET?

SERVCMD IS TARGET ROLE COMMAND SERVICE

BRA RET_INT

ENDI

5-11

WRITING A DRIVER

******************************************************************

************

* THE CODE BELOW HANDLES FINAL RETURN CODES.

FINALSTAT:

BSR POSTSTAT

POSTSTAT IS A SUBROUTINE THAT POSTS FINAL

STATUS

* POSTSTAT RETURNS THE Z BIT=1 IF STATUS IS O.K.

******************************************************************

************

* THE CODE BELOW IS A COMMON EXIT CODE FOR THIS DRIVER.

RET_OUT

BTST #13,D0

IF <EQ> THEN

RTE REQUIRED?

BSR RESTORE_REG A3 IS THE INPUT TO THIS REGISTER RESTORE

ROUTINE

RTE

EXECUTE THE RTE FOR THE SCSI FIRMWARE

ENDI

* THERE ARE ONLY TWO WAYS TO ACTUALLY ’EXIT’ THIS CALLER ROUTINE.

* 1. IS TO EXIT VIA THE EXECUTION OF AN RTE. (A TASK WAS INTERRUPTED

BY THE

SCSI BUS AND THE EXECUTION OF THE RTE WILL RESUME THAT TASK.)

* 2. A ROUTINE CALLED THIS DRIVER BY A SUBROUTINE CALL. IT IS RETURNED

TO WITH

THE EXECUTION OF AN RTS.

ALL OTHER ’EXITS’ GO BACK TO THE SCSI FIRMWARE (FOR THIS

EXAMPLE).

RTS

5-12

Interface Rules for the SCSI Firmware

* RESTORE REGISTERS FOR SCSI ROUTINE

* The driver must restore the registers the SCSI firmware has used.

* A3 is pointing to a list of the registers to restore.

* The following code is for 68010 or newer processor and could be more

* efficient if more advanced processor as 68020, 68030 is used.

Entry:

Exit:

A3 = Pointer to register list of registers to

restore.

Back to caller.

RESTORE_REG:

MOVE.L #14,D0

ADDA.L #60,A3

Number of longwords to move

= 15.

Start from bottom

of register

for MOVEM

list.

Store on the stack

RSTRLOOP MOVE.L -(A3),-(SP)

instruction.

DBRA

MOVEM.L (SP)+,D0-D7/A0-A6 Restore registers.

REST_OUT RTS

END

D0,RSTRLOOP

******************************************************************

************

Interface Rules for a Single Caller

You can use the same rules as provided for multiple callers. By doing so, a

second or third caller may later be added without the necessity of modifying

the initial caller routine. By using the rules for multiple callers, a user also

expects the firmware to do more work than would otherwise have to be done

5-13

WRITING A DRIVER

by the driver -- specifically, command queuing. If you choose to follow the

rules for multiple callers, the firmware queues command packets for you

whenever the bus is busy.

For example, if a user of the SCSI interface only has disk applications, only a

SCSI disk driver for the particular operating system may need to be written. If

the rules for multiple callers are used, then at a later time, a SCSI tape driver

for the same operating system may be added without affecting the old disk

driver (assuming that the tape driver returns are vectored through a different

vector than the SCSI disk driver). Refer to the Interface Rules for Multiple Callers

section in this chapter for details.

5-14

TARGET ROLE ROUTINES

Introduction

According to SCSI definitions, an initiator is an SCSI device that initiates a

command on the bus to be executed by the TARGET; a TARGET is an SCSI

device that is selected by an initiator and executes what is requested by the

initiator. The MVME147 is capable of playing both the initiator and TARGET

roles with the WD33C93 SCSI interface chip. Because most of the SCSI

protocol is performed outside the WD33C93, the TARGET role routines of the

MVME147 SCSI firmware provide the means of supporting command

execution and message passing for the MVME147 operating as a processor

device TARGET on the SCSI bus. As defined by the SCSI draft revisions 17 and

earlier, only three commands for processor-type devices are considered

standard; these are: SEND (0A), RECEIVE (08), and REQUEST SENSE (03).

The contents of the data sent are not defined by SCSI standard and are totally

interpretable by the user application. An entire decoding scheme could be

built around the three basic commands for interprocessor communication

over the SCSI bus.

MVME147 SCSI Firmware Background

The MVME147 SCSI firmware provides routines that supports initiator role on

the SCSI bus. Execution of disk reads, writes, and formats are provided by

read, write, and format packets, respectively. Another important support of

SCSI execution is also provided by the custom SCSI sequence packets of the

MVME147 firmware. With the custom SCSI sequence, you pass a pointer to a

particular "script" (a sequence of information transfer phase codes) and a

pointer to the data that supports this script to the firmware, along with the

code for the custom SCSI sequence and also provides a return vector for status

and processor control. With this particular interface, the firmware performs

any sequence of SCSI information transfer phases that you require. The

TARGET role routines provide the missing half for these custom SCSI

sequences -- execution of scripts in the TARGET role.

The SCSI bus makes allowance for only eight SCSI devices. Each SCSI device

is allowed to service eight peripheral devices. If all peripheral devices were

present on the SCSI bus, there would be a maximum of 64. The MVME147

SCSI firmware developes a method of indexing the devices on the SCSI bus.

This index is the "attach table", a table of 64 entries, each entry peculiar to a

TARGET ROLE ROUTINES

particular device on the SCSI bus. The indexing is accomplished by simply

splitting the 64 entries into 8 entries of 8 peripheral devices. Each block of

eight devices corresponded to each SCSI device. The MVME147 is one of these

SCSI devices. Seven other SCSI devices may be added to the SCSI bus to

perform some application. As long as there is another SCSI device that can

play the initiator role on the bus, then the MVME147 may also play the

TARGET role on the bus. The eight entries under the SCSI device entry deal

with TARGET support of eight peripheral devices. In other words, the SCSI

firmware TARGET role routines allow support of eight peripheral devices

associated with the MVME147.

The method of addressing these peripheral devices is through the concept of

logical units. Because the MVME147 supports eight logical units on the SCSI

bus, LUN 0 may be a printer, LUN 1 may be an RS-232C port, and LUNs 2

through 7 may be some I/ O devices on the VMEbus (as an example). Each

logical unit is independent of the other as far as the SCSI firmware is

concerned. To keep this independent feature, each service module for each

logical unit should provide a different return vector to the SCSI firmware.

SCSI Versus SASI Rules

As far as the SCSI firmware is concerned, a SCSI system is one that supports

arbitration, reselection, and the message-out phase. Typically, a SASI system

contains only one initiator and at least one TARGET. A SASI system with only

one initiator and no reselection clearly does not require bus arbitration because

only one SCSI device ever tries to acquire the bus. With these rules in place, it

is clear that for the MVME147 to operate both as an initiator and as a TARGET

on the SCSI bus, you must have a SCSI system; one that supports arbitration,

reselection, and the message-out phase. (The message-out phase is required

for identification of reselectability after the selection phase and for

identification of the peripheral logical unit immediately following reselection.)

If the MVME147 is to operate only as a TARGET on the SCSI bus with only one

initiator on the same bus, then you may use a SASI system with the MVME147

as a TARGET only.

MVME147 SCSI Firmware TARGET Role Structure

Requirements

The following sections describe the data structures required by the SCSI

firmware for the TARGET role custom sequence packets. Refer to Chapter 2.

Custom Sequence Packet

Custom Sequence packets are detailed in Chapter 2.

6-2

MVME147 SCSI Firmware TARGET Role Structure Requirements

Command Table pointer

Script pointer

Interrupt level 7 through 1

Return vector

TARGET enable/ TARGET sequence

Control number = MVME147 level

Peripheral device LUN (0 through 7)

Script

Below are the TARGET role script codes for SCSI bus phases.

$00 DISCONNECT

$04 COMMAND PHASE

$08 DATA-OUT PHASE

$0CDATA-IN PHASE

$10 STATUS PHASE

$14 MESSAGE-OUT PHASE

$18 MESSAGE-IN PHASE

$1CEND OF SCRIPT

$20 TARGET WAIT, NO DISCONNECT ALLOWED

$24 TARGET WAIT, DISCONNECT ALLOWED

$28 TARGET WAIT, NO DISCONNECT, DATA RECEIVED

$2CTARGET WAIT, DISCONNECT, DATA RECEIVED

Command Table

A command table is shown in the Initiator Role section in Chapter 2.

Status/ Control Byte

Link (used in the TARGET module).

Parity (implemented in the TARGET module).

DMA (implemented in the TARGET module).

CSCSI (check SCSI status).

SG (implemented with DMA in the TARGET module).

SYNC/ ASYNC (implemented in the TARGET module).

Link Pointer

Forward link pointer to the next command table (not used in

the first release).

6-3

TARGET ROLE ROUTINES

Data Area

Only one direction allowed per command. If multiple

directions of data transfer are required, linked commands

could provide a solution.

Message-In Area (user defined)

For messages to be sent to the initiator.

Message-Out Area (user defined)

258 byte maximum for extended message for messages sent

by initiator.

Command Count

The number of bytes command received in the command

area.

Command Area(s)

Commands are stored in this 12-byte-maximum area.

Status Area

This status byte is sent if the status phase is encountered in the

script.

Data Area Count

Data transfer count.

Data Area Pointer

Pointer to the data area described below. DATA-IN: to the

initiator, DATA- OUT: from the initiator.

Message-In Area Count

Number of message bytes to be sent to the initiator.

Message-In Area Pointer

Pointer to the message-in area described below. Messages

sent to the initiator.

Message-Out Area Count (not used)

Message-Out Area Pointer

Pointer to the message-out area described below. Messages

received from the initiator.

Enabling TARGET Role

1. Prepare a custom sequence packet as described in the TARGET Enable

Custom Sequence Packet section in Chapter 2, with the code of TARGET

6-4

Enabling TARGET Role

enable (word $0E = $C000), and with the following data structures

reserved for TARGET role service.

a. Command Table (384 bytes)

During the TARGET role, when the TARGET enable packet

is issued to the firmware, neither the custom command

packet nor the command table shall be deallocated because

firmware uses both areas for subsequent TARGET service.

Note

b. Message-out area (the SCSI standard allows for a 258-byte extended

message)

In SCSI terms, all transfer directions are referenced to the

initiator. For example, the data out phase is a data phase for

data OUT of the initiator and INTO the TARGET.

Therefore, the message-out area mentioned above is for

message STORAGE from the initiator to the TARGET.

c. Take over the return vector specified in the packet of 1. above. Put the

service routine address in the vector.

d. Load address register A2 with the address of the custom sequence packet

described in 1. above.

e. Enter the SCSI firmware through the FUNNEL entry point ($FFFE078E) at

interrupt level 2. (For a description of the FUNNEL module, refer to the

SCSI Firmware Entry Points section in Chapter 1.

f. Examine the returned final status for a code of $xx17. This is a signal that

the firmware has acknowledged the enable packet and the initiator

command has been received. (This status may be preceded by a $A002 if

the bus is occupied at the time that the enable packet was sent to the

firmware.)

g. The service of the TARGET LUN is now interrupt-driven by the initiator.

A selection interrupt causes the firmware to examine enabled TARGET

LUNs and load commands and/ or messages into the designated areas for

service. If a command is received for an enabled TARGET logical unit,

then the firmware returns to you with either a $xx17 final status (SCSI

mode) or an intermediate status of $xx06 (SASI mode or initiator not

supporting disconnection), indicating that the CDB has been loaded into

6-5

TARGET ROLE ROUTINES

the user command table. The service of this command is provided by you.

This service is provided by a custom SCSI sequence -- TARGET sequence,

which is described in the next section.

IMPLEMENTATION NOTE: The TARGET LUN is deciphered from the

identify message sent immediately after the selection phase. If the LUN

identified during this phase is not enabled by you, the firmware rejects the

message (by sending the MESSAGE REJECT message) and then

disconnect from the bus. If an identify message is rejected, it is a signal

that some other LUN on this MVME147 TARGET address must be

enabled, otherwise the SCSI firmware would not have responded to the

selection in the first place. If a selection interrupt is ignored because the

TARGET role was not enabled in the firmware, the firmware ignores the

interrupt after the SEL signal is removed from the bus. In any case, if this

happens, the SCSI bus is tied up unless the initiator times out and gives up

by removing its signals from the bus.

Servicing the TARGET Requests

After a particular LUN is enabled for TARGET role, a selection interrupt

begins the interrupt-driven service for TARGET role and the TARGET role

stays enabled until the system is reinitialized. (The selection interrupt enable

through the WD33C93 is turned on and only reinitialization turns the

interrupt enable off. Disabling the selection interrupt is accomplished by

clearing the select enable register in the WD33C93 and/ or turning the PCC

SCSI interrupt enable off through the module control register.) Issuing a board

reset also disables TARGET role on the MVME147.

If TARGET role is enabled, a selection of the MVME147 causes the firmware to

respond to the selection by asserting the BSY signal. The following sequence

is typical of SCSI rules.

If the ATN line is asserted with SEL, the firmware takes the SCSI bus to the

message-out phase and reads the message. The firmware then takes the SCSI

bus to the command phase, reads the command (6, 10, or 12 bytes), and stores

the command count and the command in the command table. If the received

message is "identify" and if the identified LUN has been enabled, the firmware

continues and save the messages and command in command table area. No

command interpretation is done in the firmware; this job is left for the user

application. If disconnect is allowed then next phase directed by the firmware

is the message-in phase: the DISCONNECT message is sent. Then a bus

disconnect is performed by releasing the BSY signal. The first TARGET role

6-6

Servicing the TARGET Requests

service performed by the firmware is now complete. Finishing some

housekeeping, the firmware returns to the user service routine for the selected

LUN and gives it a final status code of $xx17.

If initiator is not supporting disconnect, no message-in phase and the TARGET

role returns an intermediate status $xx06 for command received.

If firmware is not enabled, the target role will response to ’inquiry’, ’request

sense’commands with some meaningful data. Also, it will return "Not Ready"

to ’test unit ready’, ’send’, and ’send diagnostic’ commands. To all other

commands before target enabled, an ’Illegal request’ will be returned.

Now comes your turn to perform the required services.

The CDB that was received by the TARGET role firmware during the

command phase was stored in the command buffer that was allocated when

you issued the TARGET enable packet to the firmware. (The command table

pointer points to this command buffer; refer to the TARGET Enable Custom

Sequence Packet section in Chapter 2, words $08 and $0A -- command table

pointer.) You may wish to service the processor device standard commands

SEND ($0A) and RECEIVE ($08). The service of commands is totally

application driven. The SEND and RECEIVE commands are probably

sufficient to establish processor communication over the SCSI bus. Following

is an example of each service. "Example"

Example: Servicing the SEND command through the TARGET sequence

firmware packet.

STEP 1: Command Interpretation

Below is the CDB for a SEND command.

bit.....7...6...5...4...3...2...1...0...

byte 0 :

byte 1 :

0 0 0 0 1 0 1 0 (OP CODE)

l u n - - - - -

(LUN|reserved)

byte 2 : Transfer length (M S byte)

length)

(Transfer

byte 3 : Transfer length (middle byte) (Transfer

length)

byte 4 : Transfer length (L S byte)

length)

(Transfer

byte 5 :

byte)

v u - - - - f l (control

6-7

TARGET ROLE ROUTINES

v u

= vendor unique

= reserved

= flag

= link

The operation code of $0A is for the SEND command. The LUN should match

the logical unit for the MVME147 TARGET. The transfer length tells you how

many bytes are going to be exchanged during the data-out phase.

The flag and link bits are handled by the firmware and you only have to load

a "INTERMEDIATE STATUS/ GOOD STATUS" if the link bit was set and a

"GOOD STATUS" if the link bit was clear. If the link bit is set, you load a

"LINKED COMMAND COMPLETE" message into the message-in buffer. If

both the link and flag bits are set, you load a "LINKED COMMAND

COMPLETE WITH FLAG" message into the message-in buffer. If neither the

link nor the flag bits are set, you should load a "COMMAND COMPLETE"

message-into the message-in buffer. (The status byte is part of the command

table -- word $14. The message-in buffer is pointed to by words $20 and $22

of the command table.) (Link and flag features not supported on the first

release of the TARGET module.)

STEP 2: Script Preparation

The SEND command requires the following script:

$08

$10

$18

$1C

: DATA-OUT PHASE

: STATUS PHASE

: MESSAGE-IN PHASE

: END OF TARGET SCRIPT

The SCSI firmware automatically performs the arbitration

Note

and reselection of the disconnected initiator.

The

IDENTIFY message is also automatically sent to the

disconnected initiator, therefore, the initial message-in

phase should not be in the script for a SEND command.

6-8

Servicing the TARGET Requests

STEP 3: Data Preparation

a. Decode the transfer length from the command descriptor block and load

this length into the command table words $16 and $18 -- data length.

b. Decode the link bit and store the status to be sent to the initiator during the

status phase into the STATUS word (MSB) of the command table -- word

$64, even byte.

c. Decode the link and flag bits and store the proper message to be presented

during the message-in phase into the message-in buffer (pointed to by

words $20 and $22 of the command table).

d. Create a TARGET sequence custom SCSI sequence packet as described in

the TARGET Sequence Custom Sequence Packet section in Chapter 2. This

packet should contain a pointer to the script described above and to the

command table that was created or used. (You may wish to use the same

command table that was provided for the TARGET enable call to the SCSI

firmware.)

STEP 4: Call the SCSI Firmware

Point address register A2 to the packet created in Step 3d.

above and jump into the SCSI firmware through the FUNNEL

command entry.

Example: Servicing the RECEIVE command through the TARGET sequence

firmware packet.

STEP 1: Command Interpretation

Below is the CDB for a RECEIVE command.

bit.....7...6...5...4...3...2...1...0...

byte 0 :

byte 1 :

0 0 0 0 1 0 0 0 (OP CODE)

l u n - - - - -

(LUN|reserved)

byte 2 : Transfer length (M S byte)

length)

(Transfer

byte 3 : Transfer length (middle byte) (Transfer

length)

byte 4 : Transfer length (L S byte)

length)

(Transfer

byte 5 :

byte)

v u - - - - f l (control

6-9

TARGET ROLE ROUTINES

v u

= vendor unique

= reserved

= flag

= link

The operation code of $08 is for the RECEIVE command. The LUN should

match the logical unit for the MVME147 TARGET. The transfer length tells

you how many bytes are going to be exchanged during the data-out phase.

The flag and link bits should be treated in the same manner as for the SEND

command example above. (Not supported on the first release.)

STEP 2: Script Preparation

The RECEIVE command requires the following script:

$0C

$10

$18

$1C

: DATA-IN PHASE

: STATUS PHASE

: MESSAGE-IN PHASE

: END OF TARGET SCRIPT

The SCSI firmware automatically performs the arbitration

Note

and reselection of the disconnected initiator.

The

IDENTIFY message is also automatically sent to the

disconnected initiator, therefore, the initial message-in

phase should not be in the script for a RECEIVE command.

STEP 3: Data Preparation

a. Decode the transfer length from the CDB and load this length into the

command table words $16 and $18 -- data length.

b. Decode the link bit and store the status to be sent to the initiator during the

status phase into the STATUS word (MSB) of the command table -- word

$64, even byte.

6-10

Servicing the TARGET Requests

c. Decode the link and flag bits and store the proper message to be presented

during the message-in phase into the message-in buffer (pointed to by

words $20 and $22 of the command table).

d. Create a TARGET sequence custom SCSI sequence packet as described in

the TARGET Sequence Custom Sequence Packet section in Chapter 2. This

packet should contain a pointer to the script described above and to the

command table that was created or used. (You may wish to use the same

command table that was provided for the TARGET enable call to the SCSI

firmware.)

STEP 4: Call the SCSI firmware

Point address register A2 to the packet created in Step 3d

above and jump into the SCSI firmware through the FUNNEL

command entry.

After the proper service script and command table have been prepared by the

user, a second custom SCSI sequence -- TARGET sequence packet must be

issued to the firmware. This packet is intended to service the command that

was just received. A script is passed to the firmware to be executed

immediately following the reselection of the disconnected initiator. The

firmware automatically performs the message-in phase with the identify

message to reestablish the disconnected thread. This information transfer

phase (message-in) should NOT be in the script.

The phases are performed as instructed by the script until a "$1C=FINISHED"

is encountered. This is the signal for the firmware to either disconnect from

the bus or to begin service of the next part of a linked command. The link

information is passed to the firmware through the control byte of the CDB. If

the link bit is set, the firmware makes the transition to the command phase,

stores the received command and command count into the command table,

makes the transition to the message-in phase, and issues a disconnect message

followed by a SCSI bus disconnect. Some housekeeping later, the firmware

returns to the user service routine with a final status of $xx19, stating that a

command has been received following the completion of the earlier command

serviced in a link. The service process then repeats.

If the serviced command has not been linked and a disconnect has been

performed instead, the firmware cleans up some details and returns to the user

service routine with a $xx18 final status.

A custom SCSI sequence -- TARGET sequence is shown in the TARGET

Sequence Custom Packet section in Chapter 2.

6-11

TARGET ROLE ROUTINES

6-12

SCSI PACKETS

Introduction

Command packets for the SCSI functions are listed in Table 7-1. The command

packets are described in detail in the following paragraphs.

Table 7-1. SCSI Functions

SCSI

FUNCTION CODE

$00

DESCRIPTION

Read (use new read, refer to $70 below)

Write (use new write, refer to $74 below)

Attach (use new disk attach, refer to

$78 below)

$04

$08

$0C

$10

$14

$18

$1C

$20

$24

$28

Detach (all devices)

Format (with/ without defect list)

Assign Alternate Sector

Reserved

Custom SCSI Sequence (refer to Chapter 2)

SCSI Bus Reset

SCSI Controller Reset

Tape Attach (use new tape attach, refer

to $6C below)

$2C

$30

$34

$38

Erase

Rewind

Read Block Limits

Space (blocks, filemarks, sequential

filemarks, end of data)

Write Filemarks

$3C

$40

$44

$48

Verify CRC

Tape Mode Select

Tape Mode Sense

SCSI PACKETS

Table 7-2. SCSI Functions (cont’d)

SCSI

FUNCTION CODE

$4C

DESCRIPTION

Reserved

$50

$54

$58

$5C

$60

$64

$68

$6C

$70

$74

$78

$7C

Inquiry

Load/ Unload

Recover Buffer Data

Request Sense Data

Check Status

Reserve Device

Release Device

New Tape Attach

New Read (disk and tape)

New Write (disk and tape)

New Disk Attach

Open (read of first blocks of a device)

Read/Write Packet

For common command set refer to Appendix A.

DISK. Commands sent to the controller are: Read ($28), and Write ($2A).

For a read or write function, the maximum number of bytes that can be

transferred in a single call is 16Mb. If you need more, the command must be

broken up into several calls. For controller type 13, the command control field

can turn on/ off the cache within the drive. If the drive currently has cache in

the opposite state as the command control field cache bit, a mode select of page

38 is sent to the controller to turn on/ off the cache prior to the read/ write

command.

TAPE. Commands sent to the controller are: read ($08) and write ($0A).

A tape read or write operation starts at the current position and must be in the

correct mode (refer to the appropriate controller manual). To write, the

controller must be in general mode or write mode. General mode occurs after

a tape positioning command that does not read the tape data (space-to-end-of-

recorded-media). Also, the controller can be at Beginning Of Tape (BOT),

7-2

Read/ Write Packet

space-to-end-of-recorded-media, or write command. To read, the controller

must be at BOT or following a space-blocks, space-filemarks, or read

command.

The command control field gives the user the ability to read forward or reverse

(if supported by drive) and the ability to suppress illegal length indication (if

supported by drive).

DISK and TAPE.

For scatter/ gather operation, a non-zero value in the scatter/ gather count

indicates the memory and scatter/ gather address field is the address of the

scatter/ gather table. The number of sectors field must be filled in and is also

used to calculate the total byte count.

The details of a read/ write packet are shown below.

New Packet

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Memory Address (MSW) (Note 2)

Memory Address (LSW) (Note 2)

Sector Number (MSW)

Sector Number (LSW)

Number of Sectors to Transfer (MSW)

Number of Sectors to Transfer (LSW)

Scatter/ Gather Count

Command Control

Function Code (70, 74)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

7-3

SCSI PACKETS

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

$04

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

xxxxxxxx

Memory Address

(MSW)/ scatter/ gathe

table address if

scatter/ gather count

> 0

$06

$08

xxxxxxxx

Memory Address

(LSW)/ scatter/ gather

table address if

scatter/ gather count

> 0

Sector Number

(MSW)

$0A

$0C

xxxxxxxx

Sector Number (LSW)

Number of sectors to

transfer/ number

of logical

blocks/ bytes to

transfer (MSW)

(Note 7)

$0E

xxxxxxxx

Number of sectors to

transfer/ number

of logical

blocks/ bytes to

transfer (LSW)

(Note 7)

$10

Scatter/ gather count,

number of entries

7-4

Read/ Write Packet

in SG table, if zero,

SG is disabled

$12

$14

00000000

xxxxxxxx

0.......

00000000

Reserved

Command Control

Cache ON for type 13

controller only

1.......

.0......

Cache OFF for type

13 controller only

Tape read forward for

tape devices that

support this

.1......

..0.....

Tape read reverse for

tape devices that

support this

Tape do not suppress

illegal length

indication for tape

devices that support

this

..1.....

Tape suppress illegal

length indication

for tape devices that

support this

$15

$16

xxxxxxxx

00000xxx

SCSI function ($70 =

Read, $74 = Write)

Interrupt level (7

through 0)

(0 = polled mode)

(Notes 3, 5)

$17

xxxxxxxx

Vector number to use

upon return

(Notes 4, 5)

$18

$19

xxxxxxxx

Status from SCSI

firmware (byte 2)

(Note 1)

Status from SCSI

firmware (byte 3)

(Note 1)

7-5

SCSI PACKETS

Refer to Chapter 3.

NOTE

Refer to the following scatter/ gather table format.

The interrupt level of this firmware can be from level 0 to 7. It should be

kept the same throughout the firmware execution; i.e., when the user has

chosen a specific interrupt level, it must not be changed until there is no

outstanding command.

The return vector should point to the user return routine at all times for

the proper return path.

Because both the interrupt vector and the return vector use the Vector

Base Register (VBR) to locate the proper address to resume the operation,

the VBR should not be changed if there are any outstanding SCSI

commands.

During scatter/ gather operation, no automatic RETRY is performed by

SCSI firmware and the scatter/ gather table contents could be modified by

the firmware when the command is completed.

For tape, if the previous tape attach had both physical bytes per block and

logical bytes per block = 0 (variable block size). This field is number of

bytes to transfer.

Old Packet Supported for Compatibility

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Memory Address (MSW) (Note 2)

Memory Address (LSW) (Note 2)

Sector Number (MSW)

+$0A

+$0C

+$0E

+$10

Sector Number (LSW)

Number of Sectors to Transfer

Scatter/ Gather Count

7-6

Read/ Write Packet

+$12

+$14

+$16

+$18

Command Control

Function Code (00, 04)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

$00

$01

$02

00000xxx

Controller logical unit

number

00000xxx

xxxxxxxx

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

$04

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

xxxxxxxx

Memory Address

(MSW)/ scatter/ gathe

table address if

scatter/ gather count

> 0

$06

$08

xxxxxxxx

Memory Address

(LSW)/ scatter/ gather

table address if

scatter/ gather count

> 0

Sector Number

(MSW)

$0A

$0C

xxxxxxxx

Sector Number (LSW)

Number of sectors to

transfer/ number

of logical

blocks/ bytes to

transfer

$0E

$10

00000000

xxxxxxxx

00000000

xxxxxxxx

Reserved

Scatter/ gather count,

number of entries

7-7

SCSI PACKETS

in SG table, if zero,

SG is disabled

$12

$14

00000000

xxxxxxxx

0.......

00000000

Reserved

Command Control

Cache ON for type 13

controller only

1.......

.0......

Cache OFF for type

13 controller only

Tape read forward for

tape devices that

support this

.1......

..0.....

Tape read reverse for

tape devices that

support this

Tape do not suppress

illegal length

indication for tape

devices that support

this

..1.....

Tape suppress illegal

length indication

for tape devices that

support this

$15

$16

xxxxxxxx

00000xxx

SCSI function ($00 =

Read, $04 = Write)

Interrupt level (7

through 0)

(0 = polled mode)

(Notes 3, 5)

$17

xxxxxxxx

Vector number to use

upon return

(Notes 4, 5)

$18

$19

xxxxxxxx

Status from SCSI

firmware (byte 2)

(Note 1)

Status from SCSI

firmware (byte 3)

(Note 1)

7-8

Read/ Write Packet

Refer to Chapter 3.

NOTE

Refer to the following scatter/ gather table format.

The interrupt level of this firmware can be from level 0 to 7. It should be

kept the same throughout the firmware execution; i.e., when the user has

chosen a specific interrupt level, it must not be changed until there is no

outstanding command.

The return vector should point to the user return routine at all times for

the proper return path.

Because both the interrupt vector and the return vector use the Vector

Base Register (VBR) to locate the proper address to resume the operation,

the VBR should not be changed if there are any outstanding SCSI

commands.

During scatter/ gather operation, no automatic RETRY is performed by

SCSI firmware and the scatter/ gather table contents could be modified by

the firmware when the command is completed.

DMA Scatter/Gather Table Entry

Each scatter/ gather table entry has two longwords: first one is DMA memory

address, second is control/ byte count.

310

DMA MEMORY ADDRESS (32-BIT)

XXXX XXXX XXXX

| function code (3 bits)

1 = link to next entryFor example $5 is

0 = no link, last entryused here (supervisory

data space)

7-9

SCSI PACKETS

There may be any number of scatter/ gather entries.

NOTES:

The scatter/ gather table must be in local MVME147 RAM (the DMA

channel does not table walk offboard RAM).

Table address must be longword aligned.

Attach/Detach Packet (all devices)

For common command set refer to Appendix A. The following SCSI

commands are executed during an attach:

CONTROLLER

COMMAND

DEVICE

NAME

COMMAND

NOTES

SCSI

Wincheste

Reserve device

$16

Executed on attach if reserve-

on-attach/ release-on-detach bit

is set in packet. A reserve

device command is sent to the

controller. A reserve device

command can be used in a

multi-initiator SCSI environ-

ment to reserve the device.

Release device

$17

Executed on detach if reserve-

on-attach/ release-on-detach bit

is set in packet. A release

device command is sent to the

controller and the firmware

clears an internal attach flag. A

release device command can be

used in a multi-initiator SCSI

environment to release the

device.

Test unit ready

Mode sense

$00

Checks whether the selected

device is ready.

$1A

To check the block size. If the

block size in the packet is

different than the

controller/ drive setting, all

reads/ writes are blocked and

an "attach error" is returned.

7-10

Attach/ Detach Packet (all devices)

CONTROLLER

COMMAND

NAME

DEVICE

COMMAND

NOTES

TAPE

Rewind

$01

A rewind command is sent (2.0

firmware and later) because

many tape devices require the

tape to be at BOT to send a

mode select command.

Reserve device

$16

Executed on attach if reserve-

on-attach/ release-on-detach bit

is set in packet. A reserve

device command is sent to the

controller. A reserve device

command can be used in a

multi-initiator SCSI environ-

ment to reserve the device.

Release device

$17

Executed on detach if reserve-

on-attach/ release-on-detach bit

is set in packet. A release

device command is sent to the

controller, and the firmware

clears an internal attach flag. A

release device command can be

used in a multi-initiator SCSI

environment to release the

device.

Mode select

$15

$00

This command configures the

controller for operat-ional

parameters.

Test unit ready

Checks whether the selected

device is ready.

An attach is required before any other commands may be sent to the SCSI

firmware (except custom SCSI sequence or Bus Reset).

An attach call initializes the SCSI firmware pointers and internal flags. A RAM

work area is used by SCSI firmware for building internal pointers and also

contains the command sent to the SCSI controller. The RAM work area should

not be reallocated until the device is detached or reset.

7-11

SCSI PACKETS

Some SCSI controllers return a "check" status on the first command sent to

them after power-up or reset. The SCSI firmware retries the command if the

controller returns "unit attention" request sense information and if you put a

number that was one or greater into the retry field in the attach packet.

Otherwise, the request-sense data is returned to you. You can then retry the

command.

The first table below shows the details of an attach/ detach packet for disk. The

second table shows the details of a attach packet for streaming tape. A third

table details the 384-byte ($180-byte) work area specified in the attach packet

and used for all subsequent commands. The work area is normally not

examined by you except when the "additional status" bit is set (refer to the

packet status codes in Chapter 3). On most operations involving data transfer

(except scatter/ gather) in which DMA is used, the "sector number in error",

"transfer address", and "command error word" can be used to assist error

handling.

New Packet

Even Byte \

Odd Byte \

Device LUN

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

+$1C

Controller LUN

Status Byte 0

Status Byte 1 (Note 1)

Step Rate

Number of Heads

Number of Cylinders

Precompensation Cylinder

Logical Sectors per Track

SCSI Disk Attributes

Controller Type

Drive Type

Function Code (78)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Retry Count

Physical Bytes per Block

7-12

Attach/ Detach Packet (all devices)

+$1E

+$20

Pointer RAM

Work Area

(MSW)

+$22

Pointer RAM

Work Area

(LSW)

+$24

Logical Bytes per

Block

+$26

+$28

Alt Sectors per Zone

No. Alt Cyls to Reserve

$00

00000xxx

Controller logical unit

number (SCSI

address 0-7)

$01

$02

00000xxx

xxxxxxxx

Device logical unit

number (0-7)

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$05

00000000

xxxxxxxx

Reserved

Step Rate -- number

of 40 intervals per

step (a value of 0

defaults to 6 ms)

$06

$07

00000000

xxxxxxxx

Reserved

Number of heads on

drive

$08

$0A

$0C

xxxxxxxx

Number of cylinders

on drive

Precompensation

cylinder

Logical sectors per

track, physical = this

plus alternate sectors

per zone if zone =

track

$0E

$10

00000000

xxxxxxxx

00000000

xxxxxxxx

Reserved

SCSI drive attributes

7-13

SCSI PACKETS

........

.......0

.......1

......0.

FM encoding, single

density

MFM encoding,

double density

Single track density

(media TPI = ½ drive

TPI,

double step)

........

......1.

Double track density

(media TPI = drive

TPI)

........

Reserved

....0...

250K bits/ sec data

rate (5¼ inch)

........

....1...

500K bits/ sec data

rate (8 inch)

........

...0....

...1....

..0.....

Floppy media

Rigid media

No reserve on attach;

no release on detach

........

..1.....

Reserve on attach;

release on detach

........

.0......

.1......

0.......

Non-buffered seeks

Buffered seeks

Standard IBM format,

256b sectors are 128 in

track 0

........

1.......

Non-standard; all

sectors same size,

even

track 0

.......0

.......1

......0.

......1.

........

Soft-sectored media

Hard-sectored media

Fixed media drive

Removable media

drive

........

....0...

....1...

........

Reserved

Zone = track

Zone = cylinder

7-14

Attach/ Detach Packet (all devices)

$12

$13

xxxxxxxx

00000000

Controller type (refer

to controller type

table)

Drive type (0 =

random access drive)

$14

$15

00000000

xxxx1x00

Reserved

SCSI function ($08 =

attach, $78 = new

attach,

$0C = detach)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

00000000

xxxxxxxx

Reserved

Retry count: number

of SCSI commands

(if this is set to 0, the

firmware disables

correction and turns

off retries in the

controller. Also, the

firmware does not

automatically retry

the SCSI command

except

"unit attention" and

"not diagnostics".)

$1C

$1E

xxxxxxxx

Sector/ block size in

bytes (MSW)

Sector/ block size in

bytes (LSW)

7-15

SCSI PACKETS

$20

$22

xxxxxxxx

Address of 384-byte

SCSI RAM area

(MSW)

Address of 384-byte

SCSI RAM area

(LSW)

This SCSI RAM work

area cannot be

deallocated or moved

except after a detach

or reset command.

The firmware uses

this

area for the SCSI CDB

and local pointers

and variables.

$24

$26

xxxxxxxx

Logical bytes per

block must be an

integer multiple of

physical bytes per

block and if track 0 is

half the density of the

rest of the disk, then

the sectors per track

field must be an even

value. This prevents

half sector overrun of

data.

$28

xxxxxxxx

Defines the number

of alternate sectors

per

zone to reserve for

alternates. The zone

can

be described as either

a track or a cylinder,

as specified by bit 11

of the SCSI drive

7-16

Attach/ Detach Packet (all devices)

attributes (byte offset

$10).

$29

xxxxxxxx

Alternate cylinders

defines the number of

alternate cylinders

per disk that are to be

reserved at the end of

the disk for

alternates.

Old Packet Supported for Compatibility

Refer to Chapter 3.

NOTE:

Even Byte \

Odd Byte \

Device LUN

+$00

+$02

+$04

+$06

+$08

Controller LUN

Status Byte 0

Status Byte 1 (Note 1)

Step Rate

Number of Heads

Number of Cylinders

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

+$1C

+$1E

Precompensation Cylinder

Logical Sectors per Track

SCSI Disk Attributes

Controller Type

Drive Type

Function Code (08, 0C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Retry Count

Physical Bytes per Block

Alt Sectors per Zone No. Alt Cyls to Reserve

7-17

SCSI PACKETS

+$20

+$22

RAM Work Area Address (MSW)

RAM Work Area Address (LSW)

$00

00000xxx

Controller logical unit

number (SCSI

address 0-7)

$01

$02

00000xxx

xxxxxxxx

Device logical unit

number (0-7)

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$05

00000000

xxxxxxxx

Reserved

Step Rate -- number

of 40 intervals per

step (a value of 0

defaults to 6 ms)

$06

$07

00000000

xxxxxxxx

Reserved

Number of heads on

drive

$08

$0A

$0C

xxxxxxxx

Number of cylinders

on drive

Precompensation

cylinder

Logical sectors per

track, physical = this

plus alternate sectors

per zone if zone =

track

$0E

$10

00000000

xxxxxxxx

........

00000000

xxxxxxxx

.......0

Reserved

SCSI drive attributes

FM encoding, single

density

........

.......1

MFM encoding,

double density

7-18

Attach/ Detach Packet (all devices)

........

......0.

Single track density

(media TPI = ½ drive

TPI,

double step)

......1.

Double track density

(media TPI = drive

TPI)

........

Reserved

....0...

250K bits/ sec data

rate (5¼ inch)

........

....1...

500K bits/ sec data

rate (8 inch)

........

...0....

...1....

..0.....

Floppy media

Rigid media

No reserve on attach;

no release on detach

........

..1.....

Reserve on attach;

release on detach

........

.0......

.1......

0.......

Non-buffered seeks

Buffered seeks

Standard IBM format,

256b sectors are 128 in

track 0

........

1.......

Non-standard; all

sectors same size,

even

track 0

.......0

.......1

......0.

......1.

........

Soft-sectored media

Hard-sectored media

Fixed media drive

Removable media

drive

........

....0...

....1...

xxxxxxxx

........

Reserved

Zone = track

Zone = cylinder

$12

Controller type (refer

to controller type

table)

7-19

SCSI PACKETS

$13

00000000

Drive type (0 =

random access drive)

$14

$15

00000000

xxxx1x00

Reserved

SCSI function ($08 =

attach, $78 = new

attach,

$0C = detach)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

00000000

xxxxxxxx

Reserved

Retry count: number

of SCSI commands

(if this is set to 0, the

firmware disables

correction and turns

off retries in the

controller. Also, the

firmware does not

automatically retry

the SCSI command

except

"unit attention" and

"not diagnostics".)

$1C

$1E

xxxxxxxx

Sector/ block size in

bytes

Defines the number

of alternate sectors

per

zone to reserve for

alternates. The zone

can

7-20

Attach/ Detach Packet (all devices)

be described as either

a track or a cylinder,

as specified by bit 11

of the SCSI drive

attributes (byte offset

$10).

$1F

xxxxxxxx

Alternate cylinders

defines the number of

alternate cylinders

per disk that are to be

reserved at the end of

the disk for

alternates.

$20

$22

xxxxxxxx

Address of 384-byte

SCSI RAM area

(MSW)

xxxxxxxx

Address of 384-byte

SCSI RAM area

(LSW)

This SCSI RAM work

area cannot be

deallocated or moved

except after a detach

or reset command.

The firmware uses

this

area for the SCSI CDB

and local pointers

and variables.

Refer to Chapter 3.

NOTE:

Example for floppy:

3½, 5¼

3½, 5¼, 8

3½, 5¼

PCXT

MFM

3½, 5¼

PCAT

MFM

Norm Density

FM/ MFM

High Density

FM/ MFM

7-21

SCSI PACKETS

3½, 5¼

3½, 5¼, 8

3½, 5¼

250K B/ S Data

500K B/ S Data

250K B/ S Data

500K B/ S Data

Rate

Step Rate

Heads

Precompensation $50 (Note 1)

Cylinder

$50 or $4D 8 in.

$28

$50

Sectors/ Track

Attribute Word

$10

$1A

$0F

$0203

$020B

$0281

$028B

Controller Type $0F

$0F

Drive Type

Function Code

Interrupt Level

Return Vector

Retry Count

Physical Bytes/

Block

$78

$02 (Note 2)

$4E (Note 2)

$03

$02 (Note 2)

$4E (Note 2)

$03

$02 (Note 2)

$4E (Note 2)

$03

$02 (Note 2)

$4E (Note 2)

$03

$100

$200

Pointer to Work $10000

(Note 2)

$10000

(Note 2)

$100

$10000

(Note 2)

$200

$10000

(Note 2)

$200

Logical Bytes/

Block

$100

Refer to drive specification.

Up to user.

NOTE:

New Packet

Even Byte \

Odd Byte \

+$00

+$02

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

7-22

Attach/ Detach Packet (all devices)

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

+$1C

+$1E

Number of Tracks

Minimum Read Transfer

Minimum Write Transfer

Streaming Count

Speed Code

Density Code

SCSI Tape Attributes

Controller Type

Drive Type

Function Code (6C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Retry Count

Physical Bytes per Block (0 for Variable) (Note 2)

+$20

Pointer to RAM +$22

Work Area

(MSW)

Pointer to RAM

Work Area

(LSW)

+$24

Logical Bytes per

Block (0 for

Variable) (Note

+$26

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$05

00000000

Reserved

Number of tracks on

media (not used by

all

controllers

7-23

SCSI PACKETS

$07

00000000

Minimum read

transfer size (not used

by all

controllers

Reserved

$08

$09

00000000

xxxxxxxx

Minimum write

transfer size (not used

by all

controllers

Reserved

$0A

$0B

00000000

xxxxxxxx

Streaming count (not

used by all

controllers)

$0C

00000000

Speed code ($00 =

default speed)

$00 = use default

speed

$01 = lowest

speed select

$02 = higher

speed select

$0F = highest

speed select

$0D

00000000

Density code ($00 =

default density (Note

Density

Code

$00

Tape

Width

Drive

Type

Tracks

Type

All

BPI

$01

Code

1/ 2"

Use default density

Reel-to-reel Parallel

800

$02

1/ 2"

1/ 4"

Reel-to-reel Parallel

1600

6250

8000

$03

$04

4/ 9

QIC-11

Serial

Cartridge

7-24

Attach/ Detach Packet (all devices)

$05

$06

1/ 4"

1/ 2"

4/ 9

QIC-24

Cartridge

Serial

8000

3200

Reel-to-reel Parallel

$0E

$10

00000000

xxxxxxxx

........

Reserved

xxxxxxxx

.......0

SCSI tape attributes

Non-buffered writes

(Note 3)

........

xxxxxxxx

.......1

..0.....

..1.....

Buffered writes (Note

No reserve on attach;

no release on detach

Reserve on attach;

release on detach

$12

$13

Controller type (refer

to controller type

table)

00001100

Drive type

(sequential access

generic drive)

$14

$15

00000000

00101000

Reserved

SCSI function ($28 =

attach, $6C new

attach)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

xxxxxxxx

Reserved

Retry count: number

of SCSI commands

7-25

SCSI PACKETS

(if this is set to 0, the

firmware disables

correction and turns

off retries in the

controller. Also, the

firmware does not

automatically retry

the SCSI command

except

"unit attention" and

"not diagnostics".)

$1C

$1E

$20

xxxxxxxx

Physical bytes per

block (MSW) (Note 2)

Physical bytes per

block (LSW) (Note 2)

Address of 384-byte

SCSI RAM area

(MSW)

$22

$24

xxxxxxxx

Address of 384-byte

SCSI RAM area

(LSW)

Logical bytes per

block must be an

integer multiple of

physical bytes per

block

Refer to Chapter 3.

NOTE

If both are 0 then variable block size mode is used, and the field in the

read/ write packet at offset $C is the number of bytes to transfer.

Buffered writes are used to allow time for additional data to be

transferred, thus keeping the tape streaming. If non-buffered, controller

returns status only after all data has been written to the tape. If buffered,

controller returns a good status when all data has been transferred to the

buffer, although all data may not yet have been written to the tape.

For additional codes, refer to user’s manual for the drive.

Old Packet Supported for Compatibility

7-26

Attach/ Detach Packet (all devices)

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Number of Tracks

Minimum Read Transfer

Minimum Write Transfer

Streaming Count

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

+$1C

+$1E

SCSI Tape Attributes

Controller Type

Drive Type

Function Code (28)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Retry Count

Bytes per Block

+$20

RAM Work Area +$22

Address (MSW)

RAM Work Area

Address (LSW)

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

7-27

SCSI PACKETS

$04

$05

00000000

Reserved

Number of tracks on

media (not used by

all

controllers

$07

00000000

Minimum read

transfer size (not used

by all

controllers

Reserved

$08

$09

00000000

xxxxxxxx

Minimum write

transfer size (not used

by all

controllers

Reserved

$0A

$0B

00000000

xxxxxxxx

Streaming count (not

used by all

controllers)

$0C

$0E

$10

00000000

xxxxxxxx

........

00000000

xxxxxxxx

.......0

Reserved

Tape drive attributes

Non-buffered writes

(Note 2)

........

xxxxxxxx

.......1

..0.....

..1.....

Buffered writes (Note

No reserve on attach;

no release on detach

Reserve on attach;

release on detach

$12

$13

Controller type (refer

to controller type

table)

00001100

Drive type

(sequential access

generic drive)

$14

$15

00000000

00101000

Reserved

SCSI function ($28 =

attach, $6C new

attach)

7-28

Attach/ Detach Packet (all devices)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1B

xxxxxxxx

Reserved

Retry count: number

of SCSI commands

(if this is set to 0, the

firmware disables

correction and turns

off retries in the

controller. Also, the

firmware does not

automatically retry

the SCSI command

except

"unit attention" and

"not diagnostics".)

$1C

$1E

$20

xxxxxxxx

Block size in bytes

xxxxxxxx

Address of 384-byte

SCSI RAM area

(MSW)

$22

xxxxxxxx

Address of 384-byte

SCSI RAM area

(LSW)

Refer to Chapter 3.

NOTE

7-29

SCSI PACKETS

Buffered writes are used to allow time for additional data to be

transferred, thus keeping the tape streaming. If non-buffered, controller

returns status only after all data has been written to the tape. If buffered,

controller returns a good status when all data has been transferred to the

buffer, although all data may not yet have been written to the tape.

This work area is used by the SCSI firmware to build the

SCSI command and to return additional information. The

user does not build this table. Shown below are the return

parameters. This RAM work area cannot be deallocated or

moved except after a detach or reset command. The

firmware uses this area for the SCSI CDB and local pointers

and variables.

Note

Even Byte \

Odd Byte \

+$00

Reserved

+60

Block Number in Error (MSW)

Block Number in Error (LSW)

+62

+$64

+$66

+$68

SCSI Controller Status

Transfer Address (MSW)

Transfer Address (LSW)

+$6A

+$6C

+$6E

+$70

+$72

+$74

Command Error Status

Sense Data Block

Offset

7-30

Attach/ Detach Packet (all devices)

+$9E

Sense Data Block

$00

xxxxxxxx

Reserved

$60

xxxxxxxx

Block number in error

(MSW) (Note 1)

$62

$64

xxxxxxxx

Block number in error

(LSW) (Note 1)

Status byte from SCSI

controller

(unchanged)

$65

$66

xxxxxxxx

Reserved

Transfer address

(MSW) -- for a read or

write

operation only. This

is the address of the

byte to be transferred.

(Rest to 0 is scatter/

gather is used.

$68

xxxxxxxx

Transfer address

(LSW) -- for a read or

write

operation only. This

is the address of the

byte to be transferred.

(Rest to 0 is scatter/

gather is used.

7-31

SCSI PACKETS

$72

xxxxxxxx

Command error

status byte (valid

following a

command error $08) -

- SCSI command in

error.

$73

$74

xxxxxxxx

Offset within packet

xxxxxxxx

Sense data block

(controller-

dependent).

This is the

information returned

the controller

following a check

status

and a request sense

data command.

Valid information if

bit 14 (additional

status) is set

$9E

xxxxxxxx

Sense data block

Valid following an error during a read or write operation (refer to Chapter

3).

NOTE

Format Packet

For common command set operation refer to Appendix A.

The command sent to the controller is: format device ($04). The following

SCSI commands are executed:

7-32

Assign Alternate Sector Packet (SCSI)

CONTROLLER

COMMAND

DEVICE

NAME

COMMAND

NOTES

Winchester

Mode select

$15

Configures the controller for drive

operational parameters.

Format device

$04

Formats drive.

Floppy

The defect list is optional for this command. If the number of defects in the

defect list is 0, a format device command with no defects is sent to the

controller. If the field is nonzero, the defect list is sent to the controller.

The defect list is re-formatted by the SCSI firmware, if necessary, to the format

required by the controller.

Assign Alternate Sector Packet (SCSI)

The SCSI command sent to the controller is: Assign alternate block ($07).

A size error status is returned if there is not at least one entry in the defect list.

The defect list used is the user list, but with a byte count added in the second

word by the SCSI firmware.

The first table is the details of a format/ assign alternate sector packet. The

second table is the related defect list.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Number of Entries in Defect List

Pointer to Defect List (MSW)

Pointer to Defect List (LSW)

7-33

SCSI PACKETS

+$0E

+$10

+$12

+$14

+$16

+$18

Interleave Factor

Command Control

Interrupt Level

Status Byte 2

Function Code (10, 14)

Vector Number

Status Byte 3 (Note 1)

$00

$01

$02

00000xxx

Controller logical unit

number

00000xxx

xxxxxxxx

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

xxxxxxxx

Number of defects (0

= no defect list)

Pointer to defect List

(MSW)

Pointer to Defect List

(LSW)

$0A

$0C

$0E

00000000

xxxxxxxx

00000000

Reserved

Interleave factor (0 =

use drive default)

$0F

$10

$12

$14

00000000

xxxxxxxx

Reserved

00000000

Command control (0-

7) (refer to bit

definition below)

7-34

Assign Alternate Sector Packet (SCSI)

CL Complete List

Clear and no defect list is supplied. Use existing grown defect

list, no user list is supplied.

Clear and defect list is supplied. Use existing grown defect

list, add user list to the grown list.

Set and no defect list is supplied. Do not use existing grown

defect list, no user list is supplied.

Set and defect list is supplied. Do not use existing grown

defect list, use user list as the complete defect list.

DP Disable Primary List of Defects

Clear. Use manufacturer’s primary list if the controller/ drive

supports it.

Set. Do not use manufacturer’s primary list.

DC Disable Certification Process

Clear. Use certification if the controller/ drive supports it.

(Drive is certified at format time.)

Set. Do not use certification.

SF Stop Format

R Reserved

Set. Format even if a controller/ drive defect list cannot be

accessed.

Clear. Stop formatting when any of the controller/ drive

defect lists cannot be accessed.

$15

$16

xxxxxxxx

SCSI function ($10 =

format, $14 = assign

alternate

000000xx

Interrupt level (7

through 0) (0 = polled

mode

7-35

SCSI PACKETS

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

DEFECT LIST TYPE 0

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

Defect List Code = 0000 (Note 1)

Reserved (Note 1)

Sector Number (MSW) (Note 1, 2)

Sector Number (LSW) (Note 1, 2)

Sector Number (MSW) (Note 1, 2)

Sector Number (LSW) (Note 1, 2)

0 (Note 3)

0 (Note 3, 4)

7-36

Assign Alternate Sector Packet (SCSI)

0 (Note 3, 4)

DEFECT LIST TYPE 1

Even Byte \

Odd Byte \

Defect List Code = 0001

Reserved

Cylinder (MSW) (Note 2)

Cylinder (LSW) (Note 2)

Head

Sector Within Track (MSW) (Note 2)

Sector Within Track (LSW) (Note 2)

DEFECT LIST TYPE 2

Even Byte \

Odd Byte \

Defect List Code = 0002

Reserved

Cylinder (MSW) (Note 2)

Cylinder (LSW) (Note 2)

7-37

SCSI PACKETS

Head

Bytes from Index (MSW) (Note 2)

Bytes from Index (LSW) (Note 2)

$00

$02

$04

$06

00000000

xxxxxxxx

Defect list code

Reserved

xxxxxxxx

Reserved

Sector number

(MSW) (Note 5)

$08

xxxxxxxx

Sector number (LSW)

(Note 5)

xxxxxxxx

Sector number

(MSW) (Note 5)

xxxxxxxx

Sector number (LSW)

(Note 5)

The packet points to the defect list. The defect list contains defect sector

numbers in ascending order. Following the defect list, an "additional" work

area must be provided. This work area must be equal to 2N + 1 longword,

(where N = number of defects). Some controllers require the defect lists in a

different form, and if needed, the SCSI firmware builds the list in the area

provided. A defect list code of $0000 implies that the defects are specified as

physical sector numbers. Otherwise, the defect list codes and their

corresponding representation are as follows:

Code $0000 = Sector number

Code $0001 = Cylinder, head, sector number

Code $0002 = Cylinder, head, bytes from index

Filled in by you.

NOTES:

7-38

SCSI Bus Reset Packet

N entries (ascending order).

Filled in by SCSI firmware if

needed.

2N entries.

4N number of bytes.

SCSI Bus Reset Packet

This function activates the RST* (RESET) line on the SCSI bus (hardware reset).

All devices on the bus are reset and any commands that were pending are

terminated.

The SCSI firmware cleans up internal flags and the status returned to the user

is "command complete" ($00). All outstanding packets are returned with a

"reset status" ($0A). Because all of the attach table entries are cleared after this

command, the next command for any device should be an "attach".

The following table shows the details of a SCSI bus reset/ SCSI controller reset

packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Status Byte 1 (Note 1)

Function Code (20, 24)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

7-39

SCSI PACKETS

$00

00000000

Controller logical unit

number

(controller reset only)

Reserved

$01

$02

00000000

xxxxxxxx

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

$10

$12

$14

$15

00000000

xxxxxxxx

00000000

Reserved

SCSI function ($20 =

bus reset,

$24 = controller reset)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

7-40

SCSI Controller Reset Packet

This function sends a bus device reset message ($0C) to the controller specified

in the packet. All outstanding packets are returned with a "reset status" ($0A).

This command affects only the specified controller. After the controller reset

command, the user has to send an "attach" command to SCSI firmware in

order to interface with the controller again because the specified controller

attach table entry is cleared.

Some controllers do not support this message; the results

are unpredictable unless the controller supports the

controller reset message ($0C).

Note

Erase Packet

The erase command ($19) erases the entire tape in the specified drive. All

tracks are erased in one forward motion; the tape then rewinds and is

positioned at the BOT.

The tape must be positioned at BOT before this command is issued. An

attempt to erase a tape not at BOT results in an illegal request ($xx25) status.

The table below shows the erase packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

7-41

SCSI PACKETS

+$12

+$14

+$16

+$18

Function Code (2C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

$00

$01

$02

00000000

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

$10

$12

$14

$15

00000000

00101100

00000000

Reserved

SCSI function ($2C =

erase

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

7-42

Rewind Packet

Refer to Chapter 3.

NOTE:

Rewind Packet

The Rewind command ($01) rewinds the tape to the BOT. If the immediate

response bit is set, status is returned immediately, even though the controller

is still busy rewinding. If a new command is sent before the controller is

finished, a busy status may be sent to the MVME147, but the firmware

performs an internal retry after the current command is done. If the

immediate response bit is not set, status is not returned until the drive is

finished.

The SCSI firmware table shows the rewind packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Immediate Response

Function Code (30)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

00000000

Controller logical unit

number

7-43

SCSI PACKETS

$01

$02

00000000

xxxxxxxx

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

00000000

x0000000

00000000

Reserved

Immediate response

flag

0.......

Respond when

complete

1.......

00000000

00110000

Immediate response

Reserved

$0F

$10

$12

$14

$15

00000000

Reserved

SCSI function ($30 =

rewind)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

7-44

Read Block Limits Packet

The read block limits command ($05) returns the maximum and minimum

block size written on the tape. The controllers supported by the SCSI firmware

only support QIC 24 or QIC 11 type blocks which equal 512 ($200) bytes.

The table below shows the read block limits packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Returned Maximum Block Length (MSW)

Returned Maximum Block Length (LSW)

Returned Minimum Block Length

Function Code (34)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

7-45

SCSI PACKETS

$04

$06

$08

xxxxxxxx

Returned maximum

block length (MSW)

Returned maximum

block length (LSW)

Returned minimum

block length

$0A

$0C

$0E

$10

$12

$14

$15

00000000

00110100

00000000

Reserved

SCSI function ($34 =

read block limits)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Space (Blocks, Filemarks, End of Recorded Media)

Packet

The Space command ($11) is used to position the tape. There are four modes:

mode $00 =

mode $01 =

Space n blocks

Space n filemarks

7-46

Space (Blocks, Filemarks, End of Recorded Media) Packet

mode $02 =

mode $03 =

Space sequential filemarks (if supported by

drive

Space to end of recorded media

where n = number of blocks or filemarks to Space.

Some drives support spacing backwards by using negative 2’s complement

number n. Refer to the drive manual.

The table below shows the space packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Number of Data Blocks/ Filemarks (MSW)

Number of Data Blocks/ Filemarks (LSW)

Mode

+$12

+$14

+$16

+$18

Function Code (38)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

00000xxx

Controller logical unit

number

Device logical unit

number

7-47

SCSI PACKETS

$02

$03

$04

xxxxxxxx

Status from SCSI

firmware (byte 0)

(Note 1)

Status from SCSI

firmware (byte 1)

(Note 1)

xxxxxxxx

Number of

blocks/ filemarks

(MSW) (only 3

bytes used)

$06

xxxxxxxx

Number of

blocks/ filemarks

(LSW) (only 3

bytes used)

Reserved

$08

$0A

$0C

$0E

00000000

000000xx

......00

......01

......10

00000000

Reserved

Mode

Space blocks

Space filemarks

Space sequential

filemarks

......11

Space to end of

recorded media

$0F

$10

$12

$14

$15

00000000

00111000

Reserved

00000000

SCSI function ($38 =

space)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

7-48

Write Filemarks Packet

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Write Filemarks Packet

The write filemarks command ($10) writes the specified number of filemarks

to the tape.

The controller must be in general mode or write mode.

Refer to tape read/write packet for more information.

Note

The table below shows the write filemarks packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Number of Filemarks

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Function Code (3C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

7-49

SCSI PACKETS

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

$10

$12

$14

$15

xxxxxxxx

00000000

00111100

xxxxxxxx

00000000

Number of filemarks

Reserved

SCSI function ($3C =

write filemarks)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

7-50

Verify CRC Packet

The verify Cyclic Redundancy Character (CRC) command ($13) instructs the

controller to read the specified number of blocks and check the CRC of each

block. The verify begins at the current tape position and the tape is left

positioned at the end of the last block verified. No data is transferred to the

MVME147 during this operation.

The controller must be in general or read mode.

Note

The table below shows the verify CRC packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Number of Blocks (MSW)

Number of Blocks (LSW)

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Function Code (40)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

00000xxx

Controller logical unit

number

Device logical unit

number

7-51

SCSI PACKETS

$02

$03

xxxxxxxx

Status from SCSI

firmware (byte 0)

(Note 1)

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

$10

$12

$14

$15

xxxxxxxx

00000000

01000000

xxxxxxxx

00000000

Number of blocks

Reserved

SCSI function ($40 =

verify CRC)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Tape Mode Select/Sense Packet

The tape mode select command ($15) configures the controller for the specified

operational parameters.

The tape mode sense command ($1A) returns the QIC format, controller and

drive type, block size, and buffered mode.

7-52

Tape Mode Select/ Sense Packet

The table below shows the tape mode select/ sense packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Number of Tracks

Min. Read Transfer

Min. Write Transfer

Streaming Count

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

+$1A

+$1C

SCSI Drive Attributes (Notes 2, 3)

Controller Type

Drive Type (Note 3)

Function Code (44, 48)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

Bytes per Block (Note 3)

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

$04

xxxxxxxx

00000000

Status from SCSI

firmware (byte 1)

(Note 1)

Reserved

7-53

SCSI PACKETS

$05

xxxxxxxx

Number of tracks on

media (4 or 9)

$06

$07

00000000

xxxxxxxx

Reserved

Minimum read

transfer size

(controller

reconnects when it

can take specified

number

of blocks in the spec)

Reserved

$08

$09

00000000

xxxxxxxx

Minimum write

transfer size

(controller

reconnects when it

can take specified

number

of blocks in the spec)

Reserved

$0A

$0B

$0C

$0E

$10

00000000

xxxxxxxx

00000000

xxxxxxxx

........

Streaming count

Reserved

00000000

xxxxxxxx

.......0

Reserved

SCSI drive attributes

Non-buffered writes

(Note 2)

........

xxxxxxxx

.......1

Buffered Writes (Note

$12

$13

Controller type (refer

to tape attach

packet for details)

00001100

Drive type (generic

drive)

$14

$15

00000000

0100xx00

Reserved

SCSI function ($44 =

tape mode select,

$48 = sense)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode)

7-54

Inquiry Packet

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

$1A

$1C

00000000

xxxxxxxx

00000000

xxxxxxxx

Reserved

Bytes per block

Refer to Chapter 3.

NOT

Buffered writes are used to allow time for additional data to be transferred,

thus keeping the tape streaming. If non- buffered, controller returns status

only after all data has been written to the tape. If buffered, controller returns

a good status when all data has been transferred to the buffer, although all

data may not yet have been written to the tape.

Returned on Mode Sense.

Inquiry Packet

The inquiry command ($12) returns information from the controller that

identifies which controller is attached and its attributes. The format and the

number of bytes returned varies from controller to controller (refer to the

appropriate controller manual for this information).

The returned data is put in the specified address, and the length does not

exceed the data length provided; however, the actual length and content

information returned depends upon the controller.

The first table below shows the inquiry packet. The second table shows the

inquiry data return packet.

Even Byte \

Odd Byte \

7-55

SCSI PACKETS

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Inquiry Data Length

Inquiry Data Pointer (MSW)

Inquiry Data Pointer (LSW)

Function Code (50)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$05

00000000

xxxxxxxx

Reserved

Maximum inquiry

data length ($00 -

$FF)

$06

$08

xxxxxxxx

Inquiry data pointer

(MSW)

Inquiry data pointer

(LSW)

$0A

$0C

$0E

$10

$12

00000000

Reserved

7-56

Inquiry Packet

$14

$15

00000000

01000000

Reserved

SCSI function ($50 =

inquiry)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Even Byte \

Odd Byte \

Device Type

Device Type Qualifier

Response Data Format

Data Returned (Note 1)

Data Returned

+$00

+$02

+$04

+$06

+$08

SCSI Spec Version

Additional Length

Data Returned

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Data Returned

7-57

SCSI PACKETS

+$1A

+$1C

+$1E

Data Returned

$00

xxxxxxxx

Device type code (00

= direct access)

(01 = sequential

access)

(7F = logical unit not

present)

$01

$02

xxxxxxxx

0.......

1.......

00xxxxxx

.....xxx

Device type qualifier

Fixed media

Removable media

SCSI version

ANSI version (0 =

version is

unspecified)

(1 = this version)

..xxx...

xxxxxxxx

ECMA version (0 =

no claim of

compliance

to ECMA)

$03

Response data format

(01 = common

command

set)

(00 = unspecified)

$04

$05

$06

xxxxxxxx

Number of bytes

remaining

Data returned (Note

xxxxxxxx

Data returned (Note

7-58

Load/ Unload Packet

$1E

xxxxxxxx

Data returned (Note

Controller-specific.

NOTE:

Load/Unload Packet

The load/ unload command ($1B) positions the tape for removal or to BOT.

The load mode positions the tape at BOT, and the unload mode positions the

tape at End Of Tape (EOT). The retension bit causes the tape to go to BOT, then

to EOT, then to BOT for the load mode. This is done before the load or unload

function, if enabled.

If the immediate response bit is set, status is returned immediately even

though the controller is still busy. If a new command is sent before the

controller is finished, a busy error ($xx34) may be sent back to the MVME147

firmware, but the firmware performs an internal retry after the current

command is done. If the immediate bit is not set, status is not returned until

the command is finished.

The table below shows the load/ unload packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Mode Load/ Unload

+$12

7-59

SCSI PACKETS

+$14

+$16

+$18

Function Code (54)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

00000000

x00000xx

.......0

00000000

Reserved

Mode

Unload -- positions

tape at end of tape

.......1

Load -- positions tape

at beginning of tape

......0.

......1.

No retension

Retension -- go to

BOT then EOT then

BOT

(Note: Retension

is done first)

0.......

Respond when

complete

1.......

00000000

Immediate response

Reserved

$0F

$10

$12

00000000

Reserved

7-60

Recover Buffer Data Packet

Reserved

$14

$15

00000000

01010100

SCSI function ($54 =

load/ unload)

$16

00000xxx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Recover Buffer Data Packet

The recover buffer data command ($14) is used to recover the data remaining

in the controller’s buffer following an error while writing to tape. This

command returns the data not yet written to tape. The data is read and put in

the address specified.

The table below shows the recover buffer data packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Memory Address (MSW)

Memory Address (LSW)

7-61

SCSI PACKETS

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Number of Blocks

Function Code (58)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

xxxxxxxx

Memory address

(MSW)

Memory address

(LSW)

$08

$0A

$0C

$0E

$10

$12

$14

$15

00000000

xxxxxxxx

00000000

01011000

00000000

xxxxxxxx

00000000

Reserved

Number of blocks

Reserved

SCSI function ($58 =

recover buffer data)

$16

$17

000000xx

xxxxxxxx

Interrupt level (7

through 0) (0 = polled

mode)

Vector number to use

upon return

7-62

Request Sense Data Packet

$18

$19

xxxxxxxx

Status from SCSI

firmware (byte 2)

(Note 1)

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Request Sense Data Packet

The request sense data command ($03) returns the status of the controller. The

maximum length parameter and the data pointer are used to return this status.

The actual format and the number of bytes returned is controller- specific.

Refer to the appropriate controller manual for information.

The table below shows the request sense data packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Maximum Data Length

Returned Data Pointer (MSW)

Returned Data Pointer (LSW)

Function Code (5C)

Vector Number

Interrupt Level

Status Byte 2

Status Byte 3 (Note 1)

7-63

SCSI PACKETS

$00

$01

$02

00000xxx

xxxxxxxx

Controller logical unit

number

Device logical unit

number

Status from SCSI

firmware (byte 0)

(Note 1)

$03

xxxxxxxx

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$05

00000000

xxxxxxxx

Reserved

Maximum data

length

$06

$08

xxxxxxxx

Returned data

pointer (MSW)

Returned data

pointer (LSW)

$0A

$0C

$0E

$10

$12

$14

$15

00000000

01011100

00000000

Reserved

SCSI function ($5C =

request sense data)

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

7-64

Check Status Packet

Refer to Chapter 3.

NOTE:

Check Status Packet

The check status command ($60) senses a $00 test unit ready command to the

device. The returned status is in the 4 status bytes (refer to Returned Status

Command Table in Chapter 3).

The table below shows the check status packet.

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

+$08

+$0A

+$0C

+$0E

+$10

+$12

+$14

+$16

+$18

Controller LUN

Status Byte 0

Device LUN

Status Byte 1 (Note 1)

Function Code (60)

Interrupt Level

Status Byte 2

Vector Number

Status Byte 3 (Note 1)

$00

$01

00000000

Controller logical unit

number

Device logical unit

number

7-65

SCSI PACKETS

$02

$03

xxxxxxxx

Status from SCSI

firmware (byte 0)

(Note 1)

Status from SCSI

firmware (byte 1)

(Note 1)

$04

$06

$08

$0A

$0C

$0E

$10

$12

$14

$15

00000000

00101100

00000000

Reserved

SCSI function ($60 =

erase

$16

000000xx

Interrupt level (7

through 0) (0 = polled

mode)

$17

$18

xxxxxxxx

Vector number to use

upon return

Status from SCSI

firmware (byte 2)

(Note 1)

$19

xxxxxxxx

Status from SCSI

firmware (byte 3)

(Note 1)

Refer to Chapter 3.

NOTE:

Open Packet

The open packet is a read of the first blocks of a device. This command is

intended as a "safe" read that won’t overrun the byte count when the block size

of the device is unknown.

7-66

Open Packet

Even Byte \

Odd Byte \

+$00

+$02

+$04

+$06

Controller LUN

Status Byte 0

Device LUN

Status Byte 1

Memory Address

+$08

Maximum

Number of Bytes

to Transfer

Maximum Number of Logical Bytes to Transfer

+$10

+$0A

+$0C

+$0E

+$12

+$14

+$16

+$18

Command Control

Interrupt Level

Status Byte 2

Function Code (7C = open)

Vector Number

Status Byte 3

This command reads the first blocks of a disk or tape up to the maximum

number of bytes or the maximum number of blocks, whichever comes first.

If the requested number of blocks and the number of bytes match, the returned

status is $00 (good).

If the requested number of blocks result in a transfer of more bytes than

requested, the excess data is discarded and the returned status is $00 (good).

If the requested number of blocks result in a transfer of less bytes than

requested, the returned status is $10 (byte count error).

7-67

SCSI PACKETS

7-68

COMMON COMMAND SET

AND DISK OPERATION

The first high level command required to interface with a Winchester disk is

an ATTACH. An ATTACH initializes the SCSI firmware pointers and internal

flags. A RAM work area is used to build the SCSI command descriptor block,

messages sent in the message-out phase, and a place to put incoming

messages, and status. This area also contains a copy of the ATTACH packet

parameters, and two work areas to for mode sense current values and

changeable values.

The ATTACH command performs the following to a Winchester disk:

If bit 5 of attribute word is "1" (byte offset $10), The firmware sends a Reserve

Device SCSI Command ($16) to the SCSI device.

Reserve Command CDB

VALUE

COMMENTS

Command code

BYTE OFFSET

00 (Note)

LUN is inserted into bits 7-5

Reserved

Control byte: no link, no flag

NOTE: Third party reservation not supported.

If the controller code (byte offset $12) is $17 (synchronous CCS), and if this is

the first ATTACH for this device, the firmware sends an identify message

followed by a synchronous data transfer request message and a test unit ready

command.

Synchronous Data Transfer Request Message

BYTE

VALUE

COMMENTS

Identify with reselection

message

COMMON COMMAND SET AND DISK OPERATION

BYTE

VALUE

COMMENTS

Extended message

Extended message length

Synchronous data transfer

request

Transfer period (50 times 4 ns

= 200 ns

REQ/ ACK offset

Test Unit Ready Command CDB

BYTE OFFSET

VALUE

COMMENTS

Command code

LUN is inserted into bits 7-5

Reserved

Control byte: no link, no flag

The firmware sends a mode sense command for page 3, current values. The

returned block size is compared to the block size in the packet; if they are not

the same, the firmware sets a internal flag to block all subsequent read or write

commands. In this case, the firmware returns a command error ($0B) status.

Mode Sense Command CDB

BYTE OFFSET

VALUE

COMMENTS

Command code

LUN is inserted into bits 7-5

Page 3, current values

Reserved

Allocation length

Control byte: no link, no flag

The READ/ WRITE command performs the following to a Winchester disk:

A-2

If the scatter/ gather field at byte offset $10 in the user packet is not zero, the

address at offset $4 is taken as a scatter/ gather table address. Otherwise the

address is the READ/ WRITE buffer starting address.

A typical scatter/ gather table example would be:

Scatter/ Gather Table Example

ENTRY

COMMENTS

ENTRY NUMBER

0018E400

85001200

DMA memory address

Link flag, function code = 5,

byte count

0022C800

85000800

DMA memory address

Link flag, function code = 5,

byte count

00203000

05001200

DMA memory address

Link flag = 0 (last entry),

function code

= 5, byte count

The READ and WRITE commands build a ten byte command descriptor block

based on the previous ATTACH and the READ/ WRITE command.

READ/ WRITE Command CDB

VALUE

COMMENTS

Command code

BYTE OFFSET

28 (read), 2A (write)

LUN is inserted into bits 7-5

Logical block address

Reserved

(Note 1)

(Note 2)

Transfer length

Control byte: no link, no flag

A-3

COMMON COMMAND SET AND DISK OPERATION

If the previous attach command was the "old" ATTACH ($08) or the

"new" ATTACH ($78) and the physical-bytes-per-block is equal to the

logical-bytes-per-block, the logical block address is taken from the

user packet byte offset $08.

NOTES:

If the previous attach command was the "new" ATTACH ($78) and

the logical-bytes-per-block is a multiple of the physical-bytes-per-

block, the logical block address is calculated by multiplying the

starting sector number (byte offset $8) by the logical to physical ratio.

An example would be logical-bytes-per block = $400, physical-bytes-

per-block = $200, and the users starting sector number = $600. The

calculated ratio would be 2, and the new starting sector number

would be 2 * $600 = $C00.

If the previous attach command was the "old" ATTACH ($08) or the

"new" ATTACH ($78) and the physical-bytes-per-block is equal to the

logical-bytes-per-block, the number of sectors is taken from the user

packet byte offset $0C.

If the previous attach command was the "new" ATTACH ($78) and

the logical-bytes-per-block is a multiple of the physical-bytes-per-

block, the transfer length is calculated by multiplying the number of

sectors (byte offset $C) by the logical to physical ratio. An example

would be logical-bytes-per block = $400, physical-bytes-per-block =

$200, and the user number of sectors = $30. The calculated ratio

would be 2, and the transfer length would be 2 * $30 = $60.

The information for each page below is used with each format parameter listed

in the FORMAT PARAMETER PAGE. The FORMAT command performs the

following to a Winchester disk:

Mode sense for FORMAT PARAMETER PAGE 3 current values.

If no illegal request error

Mode sense for page 3 changeable values.

If any of the previous mode sense commands returned a "Illegal Request" error

status, this next step is skipped (mode sense and mode select are optional). If

the previous commands were successful, a mode select command and

parameter list is prepared.

If the attach packet value does not match the mode sense value, and if the

changeable value is not zero (some bits are changeable), try to put the attach

packet value into the field using the changeable mask.

A-4

If it won’t fit, put the attach packet parameters offset into the error field in the

command table (byte offset $72), and return a command error status in the user

packet.

Send mode select command.

Mode sense for FORMAT PARAMETER PAGE 4 current values.

If no illegal request error

Mode sense for page 4 changeable values.

If any of the previous mode sense commands returned a "Illegal Request" error

status, this next step is skipped (mode sense and mode select are optional). If

the previous commands were successful, a mode select command and

parameter list is prepared.

If the attach packet value does not match the mode sense value, and if the

changeable value is not zero (some bits are changeable), try to put the attach

packet value into the field using the changeable mask.

If it won’t fit, put the attach packet parameters offset into the error field in the

command table (byte offset $72), and return a command error status in the user

packet.

in -2 Send mode select command.

Mode sense for FORMAT PARAMETER PAGE 1 current values.

If no illegal request error

Mode sense for page 1 changeable values.

If any of the previous mode sense commands returned a "Illegal Request" error

status, this next step is skipped (mode sense and mode select are optional). If

the previous commands were successful, a mode select command and

parameter list is prepared.

If the attach packet retry count is zero (diagnostic mode), and if the changeable

value is not zero (some bits are changeable), try to disable corrections, and set

retry count to 0 using the changeable mask.

If it won’t fit, put the attach packets parameters offset into the error field in the

command table (byte offset $72), and return a command error status in the user

packet.

Send mode select command.

A-5

COMMON COMMAND SET AND DISK OPERATION

The format operation may have a defect list, if a defect list is supplied, a new

defect list is built below the user supplied defect list with the four byte header

as required by the SCSI device. Three defect list types are accepted.

type 0

type 1

type 2

User list in logical block number.

User list in head, cylinder, sector within track.

User list in head, cylinder, bytes from index.

The new defect list is built as following:

Build 4 byte defect list header:

Byte 0 =

Byte 1 =

00.

$80 ORed with bits 6-4 of byte offset $14

of format packet. These bits give the user

control certification and primary defect

list, and stop format on defect list error.

Defect list length.

Byte 2 & 3 =

Byte 4 to n =

Defect entries as needed.

No conversion is made from one defect

list type to another type.

If no defects are supplied by the user, a 4 byte defect list header is built.

Build 4 byte defect list header.

Byte 0 =

Byte 1 =

00.

$80 ORed with bits 6-4 of byte offset $14

of format packet. These bits give the user

control certification and primary defect

list, and stop format on defect list error.

Byte 2 & 3 =

00 Defect list length.

The format command descriptor block is built based on the above information

regarding defect list, defect list type, the CL bit in byte offset $14 of user format

packet, and the interleave from byte offset $0E.

A-6

Below is the Command Descriptor Block for the Format command.

Format Command CDB

VALUE

COMMENTS

Command code

BYTE OFFSET

(Note 1)

LUN is inserted, FMT data,

CMP

list, defect list format

Reserved

(Note 2)

Interleave

Control byte: no link, no flag

FMT data (bit 4) is always = 1. CMP list bit is taken

from the CL bit in the user format packet byte offset

$14. Defect list format (bits 2-0) depend on the defect

list type supplied by the user.

NOTES:

Below is a table of user defect list type and defect list

format.

User Defect List Type and Defect List Format.

DEFECT LIST

DEFECT LIST TYPE

FORMAT (BITS 2-0)

Type 0 (logical block number)

0 0 0

1 0 1

Type 1 (head, cylinder,

sector within track)

Type 0 (head, cylinder,

bytes from index)

1 0 0

Interleave is taken from the user packet byte offset $0E.

A-7

COMMON COMMAND SET AND DISK OPERATION

MVME147 SCSI Firmware: Winchester Disk Parameters.

Before formatting a Winchester disk, the MVME147 SCSI firmware sends a

mode select command for read/ write error recovery parameters (page 1) to

the controller. Below is the command descriptor block for the mode select

command:

Mode Select Command CDB

VALUE

COMMENTS

Command code

BYTE OFFSET

LUN = 0, PF = 1, SP = 0

Reserved

(Note)

Parameter list length

Control byte: no link, no flag

If all of the parameters match or are not changeable,

only the mode select header and block descriptor is

sent, and the parameter list length is be $0C.

NOTE:

If a parameter is changed based on the current,

changeable, and the packet parameter, the entire page

1 including the mode select header and the block

descriptor is sent, and the parameter list length is $18.

The first twelve bytes that are transferred during the DATA OUT phase for the

mode select command make up the mode select header, and the block

descriptor which is described below:

Mode Select Header and Block Descriptor

VALUE

COMMENTS

BYTE OFFSET

Mode Select Header

Reserved

Media type

Reserved

A-8

Block descriptor length

Block Descriptor

Reserved

Number of blocks (MSB)

Number of blocks

Number of blocks (LSB)

Reserved

Block length (MSB)

Block length

(Note)

Block length (LSB)

The block length is taken from the attach packet,

byte offset $1C, bytes per block.

NOTE:

The remaining 12 bytes that are transferred during the DATA OUT phase for

the mode select command are the page 1 parameters.

Mode Select Parameter List: Page 1 Parameters for Winchester drives

BYTE OFFSET

VALUE

COMMENTS

Page code

Page length

(Note 1)

AWRE, ARRE, TB, RC, ERR,

PER, DTE,

DCR flags

(Note 1)

(Note 2)

Read retry count

Correction span

Heads offset count

Data strobe offset count

Reserved

(Note 2)

Write retry count

Reserved

(Note 2)

Recovery time limit (MSB)

Recovery time limit (LSB)

A-9

COMMON COMMAND SET AND DISK OPERATION

If the retry field in the attach packet byte offset $1B is = 00, the

DCR (disable correction) bit is set and the read retry count field is

set to 00.

NOTES:

If the retry field in the attach packet byte offset $1B is NOT = 00,

the fields at byte 2 and 3 are left as the default value as returned

from the mode sense command.

This field is left as the default value as returned from the mode

sense command.

Before formatting a Winchester disk, the MVME147 SCSI firmware sends a

mode select command for format parameters (page 3) to the controller. Below

is the command descriptor block for the mode select command:

Mode Select Command CDB

VALUE

COMMENTS

Command code

BYTE OFFSET

LUN = 0, PF = 1, SP = 0

Reserved

(Note)

Parameter list length

Control byte: no link, no flag

If all of the parameters match or are not changeable,

only the mode select header and block descriptor is

sent, and the parameter list length is be $0C.

NOTE:

If a parameter is changed based on the current,

changeable, and the packet parameter, the entire page

3 including the mode select header and the block

descriptor is sent, and the parameter list length is $24.

The first twelve bytes that are transferred during the DATA OUT phase for the

mode select command make up the mode select header, and the block

descriptor which is described below:

Mode Select Header and Block Descriptor

A-10

VALUE

COMMENTS

BYTE OFFSET

Mode Select Header

Reserved

Media type

Reserved

Block descriptor length

Block Descriptor

Reserved

Number of blocks (MSB)

Number of blocks

Number of blocks (LSB)

Reserved

Block length (MSB)

Block length

(Note)

Block length (LSB)

The block length is taken from the attach packet,

byte offset $1C, bytes per block.

NOTE:

The remaining 24 bytes that are transferred during the DATA OUT phase for

the mode select command are the page 3 parameters.

Mode Select Parameter List: Page 3 Parameters for Winchester drives

VALUE

COMMENTS

BYTE OFFSET

Page code

Page length

(Note 1)

(Note 2)

(Note 3)

Tracks per zone (MSB)

Tracks per zone (LSB)

Alternate sectors per zone (MSB)

Alternate sectors per zone (LSB)

Alternate tracks per zone (MSB)

Alternate tracks per zone (LSB)

A-11

COMMON COMMAND SET AND DISK OPERATION

BYTE OFFSET

VALUE

COMMENTS

(Note 4)

(Note 5)

(Note 6)

(Note 7)

(Note 8)

(Note 9)

Alternate tracks per volume (MSB)

Alternate tracks per volume (LSB)

Sectors per track (MSB)

Sectors per track (LSB)

Bytes per sector (MSB)

Bytes per sector (LSB)

Interleave (MSB)

Interleave (LSB)

Track skew factor (MSB)

Track skew factor (LSB)

Cylinder skew factor (MSB)

Mode Select Parameter List: Page 3 Parameters for Winchester drives (cont’d)

VALUE

COMMENTS

BYTE OFFSET

(Note 9)

(Note 10)

(Note 11)

Cylinder skew factor (LSB)

Drive type field

Reserved

Tracks per zone is set to $0001 if bit 11 (track = zone flag) of

the attach packets attribute word (byte offset $10) is = 0.

Tracks per zone is set to the number of heads (attach packet

byte offset $07) if bit 11 (track = zone flag) of the attach

packets attribute word (byte offset $10) is = 1.

NOTES:

Alternate sectors per zone is taken from the attach packets

alternate sectors per zone field (byte offset $1E for "old"

attach ($08), or offset $28 for "new" ATTACH ($78)).

Alternate tracks per zone field is left as the default value as

returned from the mode sense command.

A-12

Alternate tracks per volume is taken from the attach

packets alternate cylinders to reserve field (byte offset $1F

for "old" attach ($08), or offset $29 for "new" ATTACH

($78)) multiplied by the number of heads (to convert to

tracks).

The number of sectors per track, logical sectors per track,

the attach packet (byte offset $0C) plus spare sectors per

zone (byte offset $1E) if zone = track bit 11 byte offset $10 =

Bytes per sector is taken from the attach packet byte offset

$1C.

Interleave is taken from the format packet byte offset $0E.

Track skew factor field is left as the default value as

returned from the mode sense command.

Cylinder skew factor field is left as the default value as

returned from the mode sense command.

10.

Drive type field bits HSEC bit are set if the hard-sectored

media (bit 8) is set in the attach packet attribute word byte

offset $10. Otherwise, the SSEC bit is set. Other bits in this

field are set to 0.

11.

This field is left as the default value as returned from the

mode sense command.

Before formatting a Winchester disk, the MVME147 SCSI firmware sends a

mode select command for drive geometry parameters (page 4) to the

controller. Below is the command descriptor block for the mode select

command:

Mode Select Command CDB

BYTE OFFSET

VALUE

COMMENTS

Command code

LUN = 0, PF = 1, SP = 0

Reserved

(Note)

Parameter list length

Control byte: no link, no flag

A-13

COMMON COMMAND SET AND DISK OPERATION

If all of the parameters match or are not changeable,

NOTE:

only the mode select header and block descriptor is

sent, and the parameter list length is be $0C.

If a parameter is changed based on the current,

changeable, and the packet parameter, the entire page

3 including the mode select header and the block

descriptor is sent, and the parameter list length is $20.

The first twelve bytes that are transferred during the DATA OUT phase for the

mode select command make up the mode select header, and the block

descriptor which is described below:

Mode Select Header and Block Descriptor

VALUE

COMMENTS

BYTE OFFSET

Mode Select Header

Reserved

Media type

Reserved

Block descriptor length

Block Descriptor

Reserved

Number of blocks (MSB)

Number of blocks

Number of blocks (LSB)

Reserved

Block length (MSB)

Block length

(Note)

Block length (LSB)

The block length is taken from the attach packet,

byte offset $1C, bytes per block.

NOTE:

The remaining 20 bytes that are transferred during the DATA OUT phase for

the mode select command are the page 4 parameters.

A-14

Mode Select Parameter List: Page 4 Parameters for Winchester drives

VALUE

COMMENTS

BYTE OFFSET

Page code

Page length

(Note 1)

(Note 2)

(Note 3)

Number of cylinders (MSB)

Number of cylinders

Number of cylinders (LSB)

Number of heads

Starting cylinder - write precomp

(MSB)

(Note 3)

Starting cylinder - write precomp

(LSB)

(Note 4)

Starting cylinder - reduced write

current (MSB)

Starting cylinder - reduced write

current

Starting cylinder - reduced write

current (LSB)

(Note 5)

(Note 6)

Drive step rate (MSB)

Drive step rate (LSB)

Landing zone cylinder (MSB)

Landing zone cylinder

Mode Select Parameter List: Page 4 Parameters for Winchester drives (cont’d)

BYTE OFFSET

VALUE

COMMENTS

(Note 6)

(Note 7)

Landing zone cylinder (LSB)

Reserved

A-15

COMMON COMMAND SET AND DISK OPERATION

Number of cylinders is taken from the attach packet byte

offset $08.

NOTES:

Number of heads is taken from the attach packet byte offset

$07.

Starting cylinder - write precomp is taken from the attach

packet byte offset $0A.

Starting cylinder - reduced write current is left as the

default value as returned from the mode sense command.

The drive step rate is specified in the attach packet, byte

offset $05 in units of 40 microseconds. This value is

converted to 100 nanoseconds units before writing to page

4 of the mode select command. A value of zero in the

attach packet causes the drive to use the default value.

Landing zone cylinder is left as the default value as

returned from the mode sense command.

This field is left as the default value as returned from the

mode sense command.

Before accessing a floppy disk on the OMTI7000, the MVME147 SCSI firmware

sends a mode select command to the controller. Below is the command

descriptor block for the mode select command:

Mode Select Command CDB

BYTE OFFSET

VALUE

COMMENTS

Command code

LUN = 0, PF = 1, SP = 0

Reserved

Parameter list length

Control byte: no link, no flag

The first twelve bytes that are transferred during the DATA OUT phase for the

mode select command make up the mode select header, and the block

descriptor which is described below:

Mode Select Header and Block Descriptor

A-16

VALUE

COMMENTS

BYTE OFFSET

Mode Select Header

Reserved

(Note 1)

Media type

Reserved

Block descriptor length

Block Descriptor

Reserved

Number of blocks (MSB)

Number of blocks

Number of blocks (LSB)

Reserved

Block length (MSB)

Block length

(Note)

Block length (LSB)

The media type is selected using bit flags in the

attach packet attributes word, offset $10.

NOTES:

ATTRIBUTE FLAGS

500K BITS/

MEDIA

ALL SECTORS

SAME BIT 7

MFM

BIT 0

TYPE

SEC BIT 3

NOTES

PCAT

8 in., FM/ MFM

(VERSAdos

double

density)

8", FM

(VERSAdos

single density)

PCXT

A-17

COMMON COMMAND SET AND DISK OPERATION

ATTRIBUTE FLAGS

MEDIA

ALL SECTORS

500K BITS/

MFM

SAME BIT 7

SEC BIT 3

BIT 0

NOTES

5 ¼ in.,

TYPE

FM/ MFM

(VERSAdos

double

density)

The block length is taken from the attach

packet, byte offset $1C, bytes per block.

The remaining 32 bytes that are transferred during the DATA OUT phase for

the mode select command are the page 5 header and parameters. The header

consists of the first two bytes listed below, the parameters are the remaining

bytes.

Mode Select Parameter List: Page 5 Parameters

VALUE

COMMENTS

BYTE OFFSET

Page code

Page length

(Note 1)

(Note 2)

(Note 3)

(Note 4)

(Note 5)

(Note 6)

Transfer rate (MSB)

Transfer rate (LSB)

Number of heads

Sectors per track

Bytes per sector (MSB)

Bytes per sector (LSB)

Number of cylinders (MSB)

Number of cylinders (LSB)

Starting cylinder - write precomp

(MSB)

(Note 6)

Starting cylinder - write precomp

(LSB)

A-18

BYTE OFFSET

VALUE

COMMENTS

(Note 6)

Starting cylinder - reduced write

current (MSB)

(Note 6)

Starting cylinder - reduced write

current (LSB)

(Note 7)

Drive step rate (MSB)

Drive step rate (LSB)

Mode Select Parameter List: Page 5 Parameters (cont’d)

VALUE

COMMENTS

Drive step pulse width

BYTE OFFSET

Head settle delay (MSB)

Head settle delay (LSB)

Motor on delay

Motor off delay

Flags: TRDY = 1, SSN = 1, MO = 1

Steps per cylinder

Write precomp level

Head load delay

(Note 8)

Head unload delay

Pin 34 definition/ pin 2 definition

Pin 4 definition/ pin 1 definition

Reserved

(Note 9)

(Note 10)

Reserved

Transfer rate is $1F4 if the floppy data rate is 500k bits/ sec.

Transfer rate is $FA if the floppy data rate is 250k bits/ sec.

This is controlled by the 5"/ 8" flag (bit 3) in the attach packet

byte offset $10.

NOTES:

Number of heads is taken from the attach packet, byte offset

$07.

A-19

COMMON COMMAND SET AND DISK OPERATION

Sectors/ track is taken from the attach packet, byte offset $0C.

The number of bytes/ sector is taken from the bytes per block

field in the attach packet, byte offset $1C.

The Number of cylinders is taken from the attach packet, byte

offset $08.

The write precompensation starting cylinder is taken from the

attach packet, byte offset $0A. The reduced write current

starting cylinder is also taken from the attach packet, byte

offset $0A (precompensation cylinder).

The drive step rate is specified in the attach packet, byte offset

$05 in units of 40 microseconds. This value is converted to 100

microsecond units before writing to page 5 of the mode select

command. A value of zero in the attach packet causes a

default of 6 milliseconds ($003C) to be written in page 5, offset

$0E.

The steps/ cylinder field is either $01 or $02 depending on the

media and drive track descriptors in SCSI disk attributes

word of the attach packet, byte offset $10. If media TPI= drive

TPI, then $01 is used in the steps/ cylinder field. If media

TPI= 1/ 2 drive TPI, then $02 is used in the steps/ cylinder

field.

Pin34/ pin2 descriptor byte. Pin 34 is selected as "Drive

Ready", and pin 2 is high/ low density select. The level on this

signal is controlled by the flag in the attach packet, byte offset

$10, bit 4. If this bit is "1", 500k bits per second is selected and

pin 2 is low. This value is decoded below:

Pin 2 and Pin 34 Definition for High Density.

PIN 2 CONTROL

PIN 34 CONTROL

BIT

COMMENTS

Pin 34 = drive

ready, low true Bit

3 = 0) Pin 2 = 0

(high density)

Pin 2 and Pin 34 Definition for Low Density.

A-20

PIN 2 CONTROL

PIN 34 CONTROL

BIT

COMMENTS

Pin 34 = drive

ready, low true Bit

3 = 0) Pin 2 = 1

(low density)

10.

This field is left as the default value as returned from the

mode sense command.

A-21

COMMON COMMAND SET AND DISK OPERATION

A-22

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