Texas Instruments TMS320DM644x User Manual

TMS320DM644x DMSoC  
Multimedia Card (MMC)/Secure Digital (SD)  
Card Controller  
User's Guide  
Literature Number: SPRUE30B  
September 2006  
Contents  
Preface ............................................................................................................................... 7  
1
Introduction................................................................................................................ 9  
1.1  
1.2  
1.3  
1.4  
1.5  
Purpose of the Peripheral....................................................................................... 9  
Features ........................................................................................................... 9  
Functional Block Diagram....................................................................................... 9  
Supported Use Case Statement.............................................................................. 10  
Industry Standard(s) Compliance Statement ............................................................... 10  
2
Peripheral Architecture .............................................................................................. 10  
2.1  
2.2  
2.3  
2.4  
2.5  
2.6  
2.7  
2.8  
2.9  
Clock Control.................................................................................................... 12  
Signal Descriptions ............................................................................................. 13  
Protocol Descriptions........................................................................................... 13  
Data Flow in the Input/Output FIFO.......................................................................... 15  
Data Flow in the Data Registers (MMCDRR and MMCDXR)............................................. 17  
FIFO Operation During Card Read Operation .............................................................. 19  
FIFO Operation During Card Write Operation .............................................................. 21  
Reset Considerations .......................................................................................... 23  
Initialization ...................................................................................................... 23  
2.10 Interrupt Support................................................................................................ 27  
2.11 DMA Event Support ............................................................................................ 28  
2.12 Power Management............................................................................................ 28  
2.13 Emulation Considerations ..................................................................................... 28  
Procedures for Common Operations ........................................................................... 29  
3
3.1  
3.2  
3.3  
3.4  
3.5  
3.6  
3.7  
3.8  
3.9  
Card Identification Operation.................................................................................. 29  
MMC/SD Mode Single-Block Write Operation Using CPU................................................ 32  
MMC/SD Mode Single-Block Write Operation Using the EDMA ......................................... 34  
MMC/SD Mode Single-Block Read Operation Using the CPU ........................................... 34  
MMC/SD Mode Single-Block Read Operation Using EDMA.............................................. 35  
MMC/SD Mode Multiple-Block Write Operation Using CPU .............................................. 36  
MMC/SD Mode Multiple-Block Write Operation Using EDMA............................................ 38  
MMC/SD Mode Multiple-Block Read Operation Using CPU.............................................. 38  
MMC/SD Mode Multiple-Block Read Operation Using EDMA............................................ 39  
4
Registers.................................................................................................................. 40  
4.1  
4.2  
4.3  
4.4  
4.5  
4.6  
4.7  
4.8  
4.9  
MMC Control Register (MMCCTL) ........................................................................... 41  
MMC Memory Clock Control Register (MMCCLK)......................................................... 42  
MMC Status Register 0 (MMCST0) .......................................................................... 43  
MMC Status Register 1 (MMCST1) .......................................................................... 45  
MMC Interrupt Mask Register (MMCIM)..................................................................... 46  
MMC Response Time-Out Register (MMCTOR) ........................................................... 47  
MMC Data Read Time-Out Register (MMCTOD) .......................................................... 48  
MMC Block Length Register (MMCBLEN) .................................................................. 49  
MMC Number of Blocks Register (MMCNBLK) ............................................................ 50  
4.10 MMC Number of Blocks Counter Register (MMCNBLC).................................................. 50  
4.11 MMC Data Receive Register (MMCDRR)................................................................... 51  
4.12 MMC Data Transmit Register (MMCDXR) .................................................................. 51  
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4.13 MMC Command Register (MMCCMD) ...................................................................... 52  
4.14 MMC Argument Register (MMCARGHL) .................................................................... 54  
4.15 MMC Response Registers (MMCRSP0-MMCRSP7) ...................................................... 55  
4.16 MMC Data Response Register (MMCDRSP)............................................................... 57  
4.17 MMC Command Index Register (MMCCIDX)............................................................... 57  
4.18 MMC FIFO Control Register (MMCFIFOCTL) .............................................................. 58  
Appendix A Revision History ............................................................................................. 59  
4
Contents  
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List of Figures  
1
MMC/SD Card Controller Block Diagram ............................................................................... 10  
MMC/SD Controller Interface Diagram .................................................................................. 11  
MMC Configuration and SD Configuration Diagram................................................................... 11  
MMC/SD Controller Clocking Diagram .................................................................................. 12  
MMC/SD Mode Write Sequence Timing Diagram ..................................................................... 14  
MMC/SD Mode Read Sequence Timing Diagram ..................................................................... 15  
FIFO Operation Diagram .................................................................................................. 16  
Little-Endian Access to MMCDXR/MMCDRR from the ARM CPU or the EDMA.................................. 17  
Big-Endian Access to MMCDXR/MMCDRR from the ARM CPU or the EDMA.................................... 18  
FIFO Operation During Card Read Diagram ........................................................................... 20  
FIFO Operation During Card Write Diagram ........................................................................... 22  
MMC Card Identification Procedure ..................................................................................... 30  
SD Card Identification Procedure ........................................................................................ 31  
MMC/SD Mode Single-Block Write Operation.......................................................................... 33  
MMC/SD Mode Single-Block Read Operation.......................................................................... 35  
MMC/SD Multiple-Block Write Operation ............................................................................... 37  
MMC/SD Mode Multiple-Block Read Operation........................................................................ 39  
MMC Control Register (MMCCTL)....................................................................................... 41  
MMC Memory Clock Control Register (MMCCLK)..................................................................... 42  
MMC Status Register 0 (MMCST0)...................................................................................... 43  
MMC Status Register 1 (MMCST1)...................................................................................... 45  
MMC Interrupt Mask Register (MMCIM) ................................................................................ 46  
MMC Response Time-Out Register (MMCTOR)....................................................................... 47  
MMC Data Read Time-Out Register (MMCTOD)...................................................................... 48  
MMC Block Length Register (MMCBLEN).............................................................................. 49  
MMC Number of Blocks Register (MMCNBLK) ........................................................................ 50  
MMC Number of Blocks Counter Register (MMCNBLC).............................................................. 50  
MMC Data Receive Register (MMCDRR)............................................................................... 51  
MMC Data Transmit Register (MMCDXR).............................................................................. 51  
MMC Command Register (MMCCMD) .................................................................................. 52  
Command Format .......................................................................................................... 53  
MMC Argument Register (MMCARGHL)................................................................................ 54  
MMC Response Register 0 and 1 (MMCRSP01) ...................................................................... 55  
MMC Response Register 2 and 3 (MMCRSP23) ...................................................................... 55  
MMC Response Register 4 and 5 (MMCRSP45) ...................................................................... 55  
MMC Response Register 6 and 7 (MMCRSP67) ...................................................................... 55  
MMC Data Response Register (MMCDRSP) .......................................................................... 57  
MMC Command Index Register (MMCCIDX) .......................................................................... 57  
MMC FIFO Control Register (MMCFIFOCTL).......................................................................... 58  
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5
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38  
39  
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List of Figures  
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List of Tables  
1
MMC/SD Controller Pins Used in Each Mode.......................................................................... 13  
MMC/SD Mode Write Sequence ......................................................................................... 14  
MMC/SD Mode Read Sequence ......................................................................................... 15  
Description of MMC/SD Interrupt Requests ............................................................................ 27  
Multimedia Card/Secure Digital (MMC/SD) Card Controller Registers.............................................. 40  
MMC Control Register (MMCCTL) Field Descriptions................................................................. 41  
MMC Memory Clock Control Register (MMCCLK) Field Descriptions .............................................. 42  
MMC Status Register 0 (MMCST0) Field Descriptions ............................................................... 43  
MMC Status Register 1 (MMCST1) Field Descriptions ............................................................... 45  
MMC Interrupt Mask Register (MMCIM) Field Descriptions .......................................................... 46  
MMC Response Time-Out Register (MMCTOR) Field Descriptions ................................................ 47  
MMC Data Read Time-Out Register (MMCTOD) Field Descriptions................................................ 48  
MMC Block Length Register (MMCBLEN) Field Descriptions........................................................ 49  
MMC Number of Blocks Register (MMCNBLK) Field Descriptions.................................................. 50  
MMC Number of Blocks Counter Register (MMCNBLC) Field Descriptions ....................................... 50  
MMC Data Receive Register (MMCDRR) Field Descriptions ........................................................ 51  
MMC Data Transmit Register (MMCDXR) Field Descriptions........................................................ 51  
MMC Command Register (MMCCMD) Field Descriptions............................................................ 52  
Command Format .......................................................................................................... 53  
MMC Argument Register (MMCARGHL) Field Descriptions ......................................................... 54  
R1, R3, R4, R5, or R6 Response (48 Bits) ............................................................................. 56  
R2 Response (136 Bits) ................................................................................................... 56  
MMC Data Response Register (MMCDRSP) Field Descriptions .................................................... 57  
MMC Command Index Register (MMCCIDX) Field Descriptions .................................................... 57  
MMC FIFO Control Register (MMCFIFOCTL) Field Descriptions ................................................... 58  
Document Revision History ............................................................................................... 59  
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A-1  
6
List of Tables  
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Preface  
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Read This First  
About This Manual  
This manual describes the multimedia card (MMC)/secure digital (SD) card controller in the  
TMS320DM644x Digital Media System-on-Chip (DMSoC). The MMC/SD card is used in a number of  
applications to provide removable data storage. The MMC/SD controller provides an interface to external  
MMC and SD cards. The MMC/SD protocol performs the communication between the MMC/SD controller  
and MMC/SD card(s).  
Notational Conventions  
This document uses the following conventions.  
Hexadecimal numbers are shown with the suffix h. For example, the following number is 40  
hexadecimal (decimal 64): 40h.  
Registers in this document are shown in figures and described in tables.  
Each register figure shows a rectangle divided into fields that represent the fields of the register.  
Each field is labeled with its bit name, its beginning and ending bit numbers above, and its  
read/write properties below. A legend explains the notation used for the properties.  
Reserved bits in a register figure designate a bit that is used for future device expansion.  
Related Documentation From Texas Instruments  
The following documents describe the TMS320DM644x Digital Media System-on-Chip (DMSoC). Copies  
of these documents are available on the Internet at www.ti.com. Tip: Enter the literature number in the  
The current documentation that describes the DM644x DMSoC, related peripherals, and other technical  
collateral, is available in the C6000 DSP product folder at: www.ti.com/c6000.  
SPRUE14 TMS320DM644x DMSoC ARM Subsystem Reference Guide. Describes the ARM  
subsytem in the TMS320DM644x Digital Media System-on-Chip (DMSoC). The ARM subsystem is  
designed to give the ARM926EJ-S (ARM9) master control of the device. In general, the ARM is  
responsible for configuration and control of the device; including the DSP subsystem, the video  
processing subsystem, and a majority of the peripherals and external memories.  
SPRUE15 TMS320DM644x DMSoC DSP Subsystem Reference Guide. Describes the digital signal  
processor (DSP) subsystem in the TMS320DM644x Digital Media System-on-Chip (DMSoC).  
SPRUE19 TMS320DM644x DMSoC Peripherals Overview Reference Guide. Provides an overview  
and briefly describes the peripherals available on the TMS320DM644x Digital Media  
System-on-Chip (DMSoC).  
SPRAA84 TMS320C64x to TMS320C64x+ CPU Migration Guide. Describes migrating from the  
Texas Instruments TMS320C64x digital signal processor (DSP) to the TMS320C64x+ DSP. The  
objective of this document is to indicate differences between the two cores. Functionality in the  
devices that is identical is not included.  
SPRU732 TMS320C64x/C64x+ DSP CPU and Instruction Set Reference Guide. Describes the CPU  
architecture, pipeline, instruction set, and interrupts for the TMS320C64x and TMS320C64x+ digital  
signal processors (DSPs) of the TMS320C6000 DSP family. The C64x/C64x+ DSP generation  
comprises fixed-point devices in the C6000 DSP platform. The C64x+ DSP is an enhancement of  
the C64x DSP with added functionality and an expanded instruction set.  
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Related Documentation From Texas Instruments  
SPRU871 TMS320C64x+ DSP Megamodule Reference Guide. Describes the TMS320C64x+ digital  
signal processor (DSP) megamodule. Included is a discussion on the internal direct memory access  
(IDMA) controller, the interrupt controller, the power-down controller, memory protection, bandwidth  
management, and the memory and cache.  
SPRAAA6 EDMA v3.0 (EDMA3) Migration Guide for TMS320DM644x DMSoC. Describes migrating  
from the Texas Instruments TMS320C64x digital signal processor (DSP) enhanced direct memory  
access (EDMA2) to the TMS320DM644x Digital Media System-on-Chip (DMSoC) EDMA3. This  
document summarizes the key differences between the EDMA3 and the EDMA2 and provides  
guidance for migrating from EDMA2 to EDMA3.  
Trademarks  
SD is a trademark of SanDisk.  
8
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User's Guide  
SPRUE30BSeptember 2006  
Multimedia Card (MMC)/Secure Digital (SD) Card  
Controller  
1
Introduction  
This document describes the multimedia card (MMC)/secure digital (SD) card controller in the  
TMS320DM644x Digital Media System-on-Chip (DMSoC).  
1.1 Purpose of the Peripheral  
A number of applications use the multimedia card (MMC)/secure digital (SD) card to provide removable  
data storage. The MMC/SD card controller provides an interface to external MMC and SD cards. The  
communication between the MMC/SD card controller and MMC/SD card(s) is performed according to the  
MMC/SD protocol.  
1.2 Features  
The MMC/SD card controller has the following features:  
Supports interface to multimedia cards (MMC)  
Supports interface to secure digital (SD) memory cards  
Ability to use the MMC/SD protocol  
Programmable frequency of the clock that controls the timing of transfers between the MMC/SD  
controller and memory card  
256-bit read/write FIFO to lower system overhead  
Signaling to support enhanced direct memory access (EDMA) transfers (slave)  
20 MHz maximum clock to MMC (specification 3.31)  
50 MHz maximum clock to SD (specification version 1.1)  
1.3 Functional Block Diagram  
The MMC/SD card controller transfers data between the ARM and the EDMA controller on one side and  
the MMC/SD card on the other side, as shown in Figure 1. This means you have a choice of performing  
data transfers using the CPU or EDMA as a mechanism to move data between the device memory and  
the FIFO. The ARM and the EDMA controller can read from or write to the data in the card by accessing  
the registers in the MMC/SD controller.  
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Peripheral Architecture  
Figure 1. MMC/SD Card Controller Block Diagram  
ARM CPU  
MMC/SD  
interface  
MMC/SD  
card  
interface  
Status  
DMA requests  
Interrupts  
CLK  
divider  
and  
registers  
FIFO  
1.4 Supported Use Case Statement  
The MMC/SD card controller supports the following user cases:  
MMC/SD card identification  
MMC/SD single-block read using CPU  
MMC/SD single-block read using EDMA  
MMC/SD single-block write using CPU  
MMC/SD single-block write using EDMA  
MMC/SD multiple-block read using CPU  
MMC/SD multiple-block read using EDMA  
MMC/SD multiple-block write using CPU  
MMC/SD multiple-block write using EDMA  
1.5 Industry Standard(s) Compliance Statement  
The MMC/SD card controller supports the following industry standards (with the exception noted below):  
MMC (Multimedia Card) Specification V3.31  
SD (Secure Digital) Physical Layer Specification V1.1  
The information in this document assumes that you are familiar with these standards.  
The MMC/SD controller does not support the SPI mode of operation.  
2
Peripheral Architecture  
The MMC/SD controller uses the MMC/SD protocol to communicate with the MMC/SD cards. You can  
configure the MMC/SD controller to work as an MMC or SD controller, based on the type of card the  
controller is communicating with. Figure 2 summarizes the MMC/SD mode interface. Figure 3 illustrates  
how the controller interfaces to the cards in MMC/SD mode.  
In the MMC/SD mode, the MMC controller supports one or more MMC/SD cards. Regardless of the  
number of cards connected, the MMC/SD controller selects one by using identification broadcast on the  
data line. The following MMC/SD controller pins are used:  
CMD: This pin is used for two-way communication between the connected card and the MMC/SD  
controller. The MMC/SD controller transmits commands to the card and the memory card drives  
responses to the commands on this pin.  
DAT0 or DAT0-3: MMC cards only use one data line (DAT0) and SD cards use one or four data lines.  
The number of DAT pins (the data bus width) is set by the WIDTH bit in the MMC control register  
(MMCCTL), see Section 4.1).  
CLK: This pin provides the clock to the memory card from the MMC/SD controller.  
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Peripheral Architecture  
Figure 2. MMC/SD Controller Interface Diagram  
MMCs or SD cards  
ARM  
MMC/SD  
controller  
Native  
signals  
CMD  
Native packets  
DAT0 or DAT0−3  
CLK  
Memory  
EDMA  
Figure 3. MMC Configuration and SD Configuration Diagram  
MMC/SD configuration  
MMC/SD controller  
MMC and SD (1−bit mode)  
SD_CLK  
SD_CMD  
CLK  
CMD  
DAT0  
SD_DATA0  
SD_DATA1  
SD_DATA2  
SD_DATA3  
SD configuration  
MMC/SD controller  
SD card (4−bit mode)  
SD_CLK  
SD_CMD  
CLK  
CMD  
DAT0  
DAT1  
DAT2  
DAT3  
SD_DATA0  
SD_DATA1  
SD_DATA2  
SD_DATA3  
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Peripheral Architecture  
2.1 Clock Control  
There are two clocks, the function clock and the memory clock, in the MMC/SD controller (Figure 4).  
The function clock determines the operational frequency of the MMC/SD controller and is the input clock  
to the MMC/SD card(s). The MMC/SD controller is capable of operating with a function clock up to  
100 MHz.  
The memory clock appears on the SD_CLK pin of the MMC/SD controller interface. The memory clock  
controls the timing of communication between the MMC/SD controller and the connected memory card.  
The memory clock is generated by dividing the function clock in the MMC/SD controller. The divide-down  
value is set by CLKRT bits in the MMC memory clock control register (MMCCLK) and is determined by the  
following equation:  
memory clock frequency = function clock frequency/(2 × (CLKRT + 1))  
Figure 4. MMC/SD Controller Clocking Diagram  
MMC/SD controller  
MMCCLK  
(CLKRT)  
Memory clock  
on CLK pin  
MMC/SD  
input clock  
MMC/SD  
card  
Function clock for  
MMC/SD controller  
(1) Maximum memory clock frequency in MMC card can be 20 MHz.  
(2) Maximum memory clock frequency in SD card can be 50 MHz.  
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Peripheral Architecture  
2.2 Signal Descriptions  
Table 1 shows the MMC/SD controller pins that each mode uses. The MMC/SD protocol uses the clock,  
command (two-way communication between the MMC controller and memory card), and data (DAT0 for  
MMC card, DAT0-3 for SD card) pins.  
Table 1. MMC/SD Controller Pins Used in Each Mode  
Function  
MMC and SD (1-bit mode)  
Communications  
SD (4-bit mode)  
Communications  
Pin  
Type(1)  
O
CLK  
Clock line  
Clock line  
CMD  
DAT0  
DAT1  
DAT2  
DAT3  
I/O  
Command line  
Data line 0  
(Not used)  
(Not used)  
(Not used)  
Command line  
Data line 0  
Data line 1  
Data line 2  
Data line 3  
I/O  
I/O  
I/O  
I/O  
(1) I = input to the MMC controller; O = output from the MMC controller.  
2.3 Protocol Descriptions  
The MMC/SD controller follows the MMC/SD protocol for completing any kind of transaction with the  
multimedia card and secure digital cards. For more detailed information, refer to the supported MMC and  
SD specifications in Section 1.5.  
2.3.1  
MMC/SD Mode Write Sequence  
Figure 5 and Table 2 show the signal activity when the MMC/SD controller is in the MMC/SD mode and is  
writing data to a memory card. The same block length must be defined in the MMC/SD controller and in  
the memory card before initiating a data write. In a successful write protocol sequence, the following steps  
occur:  
The MMC/SD controller requests the CSD content.  
The card receives the command and sends the content of the CSD register as its response.  
If the desired block length, WRITE_BL_LEN value, is different from the default value determined from  
the response, the MMC/SD controller sends the block length command.  
The card receives the command and sends responses to the command.  
The MMC/SD controller requests the card to change states from standby to transfer.  
The card receives the command and sends responses to the command.  
The MMC/SD controller sends a write command to the card.  
The card receives the command and sends responses to the command.  
The MMC/SD controller sends a block of data to the card.  
The card sends the CRC status to the MMC/SD controller.  
The card sends a low BUSY bit until all of the data has been programmed into the flash memory inside  
the card.  
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Peripheral Architecture  
Figure 5. MMC/SD Mode Write Sequence Timing Diagram  
CMD  
Data  
Busy  
low  
2 CRC bytes  
Start  
bit  
End  
bit  
Start  
bit  
End  
bit  
CLK  
Table 2. MMC/SD Mode Write Sequence  
Portion of the  
Sequence  
Description  
Write command: A 6-byte WRITE_BLOCK command token is sent from the ARM to the card.  
WR CMD  
CMD RSP  
Command response: The card sends a 6-byte response of type R1 to acknowledge the WRITE_BLOCK to the  
ARM.  
DAT BLK  
Data block: The ARM writes a block of data to the card. The data content is preceded by one start bit and is  
followed by two CRC bytes and one end bit.  
CRC STAT  
CRC status: The card sends a one byte CRC status information, which indicates to the ARM whether the data has  
been accepted by the card or rejected due to a CRC error. The CRC status information is preceded by one start  
bit and is followed by one end bit.  
BSY  
BUSY bit: The CRC status information is followed by a continuous stream of low busy bits until all of the data has  
been programmed into the flash memory on the card.  
2.3.2  
MMC/SD Mode Read Sequence  
Figure 6 and Table 3 show the signal activity when the MMC controller is in the MMC/SD mode and is  
reading data from a memory card. The same block length must be defined in the MMC controller and in  
the memory card before initiating a data read. In a successful read protocol sequence, the following steps  
occur:  
The MMC/SD controller requests for the CSD content.  
The card receives the command and sends the content of the CSD register as its response.  
If the desired block length, READ_BL_LEN value, is different from the default value determined from  
the response, the MMC/SD controller sends the block length command.  
The card receives the command and sends responses to the command.  
The MMC/SD controller requests the card to change state from stand-by to transfer.  
The card receives the command and sends responses to the command.  
The MMC/SD controller sends a read command to the card.  
The card drives responses to the command.  
The card sends a block of data to the ARM.  
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Peripheral Architecture  
Figure 6. MMC/SD Mode Read Sequence Timing Diagram  
CMD  
1 transfer  
source bit  
2 CRC  
bytes  
Data  
CLK  
Start  
bit  
End  
bit  
Table 3. MMC/SD Mode Read Sequence  
Portion of the  
Sequence  
Description  
RD CMD  
Read command: A 6-byte READ_SINGLE_BLOCK command token is sent from the ARM to the card.  
CMD RSP  
Command response: The card sends a response of type R1 to acknowledge the READ_SINGLE_BLOCK  
command to the ARM.  
DAT BLK  
Data block: The card sends a block of data to the ARM. The data content is preceded by a start bit and is  
followed by two CRC byte and an end bit.  
2.4 Data Flow in the Input/Output FIFO  
The MMC/SD controller contains a single 256-bit FIFO that is used for both reading data from the memory  
card and writing data to the memory card (see Figure 7). The FIFO is organized as 32 eight-bit entries.  
The conversion from the 32-bit bus to the byte format of the FIFO follows the little-endian convention  
(details are provided in later sections). The read and write FIFOs act as an interim location to store data  
transferred from/to the card momentarily via the CPU or EDMA. The FIFO includes logic to generate  
EDMA events and interrupts based on the amount of data in the FIFO and a programmable number of  
bytes received/transmitted. Flags are set when the FIFO is full or empty.  
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Peripheral Architecture  
A high-level operational description is as follows:  
Data is written to the FIFO through the MMC data transmit register (MMCDXR). Data is read from the  
FIFO through the MMC data receive register (MMCDRR). This is true for both the CPU and EDMA  
driven transactions; however, for the EDMA transaction, the EDMA access to the FIFO is transparent.  
The ACCWD bits in the MMC FIFO control register (MMCFIFOCTL) determines the behavior of the  
FIFO full (FIFOFUL) and FIFO empty (FIFOEMP) status flags in the MMC status register 1 (MMCST1):  
If ACCWD = 00b:  
FIFO full is active when the write pointer + 4 > read pointer  
FIFO empty is active when the write pointer - 4 < read pointer  
If ACCWD = 01b:  
FIFO full is active when the write pointer + 3 > read pointer  
FIFO empty is active when the write pointer - 3 < read pointer  
If ACCWD = 10b:  
FIFO full is active when the write pointer + 2 > read pointer  
FIFO empty is active when the write pointer - 2 < read pointer  
If ACCWD = 11b:  
FIFO full is active when the write pointer + 1 > read pointer  
FIFO empty is active when the write pointer - 1 < read pointer  
Figure 7. FIFO Operation Diagram  
Transmission of data  
ARM/EDMA reads/writes  
Write Read  
Step 1:  
Step 2:  
Step 3:  
Step 4:  
Set FIFO reset  
Set FIFO direction  
EDMA driven transaction  
EDMA  
request  
FIFO  
CPU driven transaction:  
Fill the FIFO by writing to  
Pointer increment  
or decrease  
is created  
MMCDXR (only first time)  
or every 128 or 256−bits  
transmitted and DXRDYINT  
EDMA event  
128 or 256 bit  
interrupt is generated  
8−bit x 32  
(256−bit)  
FIFO  
Step 5:  
Step 6:  
EDMA send xmit data  
If DXR ready is active,  
FIFO −> 16−bit DXR  
EDMA event  
128 or 256 bit  
EDMA event  
the end of a  
transfer  
Reception of data  
Pointer increment  
or decrease  
FIFO  
Step 1:  
Step 2:  
Step 3:  
Set FIFO reset  
Set FIFO direction  
If DRR ready is active,  
16−bit DRR −> FIFO  
DXR  
DRR  
Step 4:  
Step 5:  
EDMA driven transaction  
DRRDYINT interrupt occur  
when FIFO every 128 or  
256−bits of data received  
by FIFO  
16−bit DXR  
16−bit DRR  
Step 6:  
EDMA read reception data  
16−bit DXR  
shifter  
16−bit DRR  
shifter  
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2.5 Data Flow in the Data Registers (MMCDRR and MMCDXR)  
The CPU or EDMA controller can read 32 bits at a time from the FIFO by reading the MMC data receive  
register (MMCDRR) and write 32 bits at a time to the FIFO by writing to the MMC data transmit register  
(MMCDXR). However, since the memory card is an 8-bit device, it transmits or receives one byte at a  
time. Figure 8 and Figure 9 show how the data-size difference is handled by the data registers in  
little-endian and big-endian configurations, respectively.  
Figure 8. Little-Endian Access to MMCDXR/MMCDRR from the ARM CPU or the EDMA  
FIFO  
MMCDRR or MMCDXR registers  
3
0
0
0
0
1st  
2nd  
3rd  
4th  
4th  
3rd  
2nd  
1st  
1st  
1st  
1st  
Support byten = ”1111”  
3
1st  
2nd  
3rd  
3rd  
2nd  
Support byten = ”0111”  
3
1st  
2nd  
2nd  
Support byten = ”0011”  
3
1st  
Support byten = ”0001”  
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Figure 9. Big-Endian Access to MMCDXR/MMCDRR from the ARM CPU or the EDMA  
3
0
1st  
2nd  
3rd  
4th  
1st  
2nd  
3rd  
4th  
Support byten = ”1111”  
3
0
0
0
1st  
2nd  
3rd  
1st  
2nd  
3rd  
Support byten = ”1110”  
3
1st  
1st  
2nd  
2nd  
Support byten = ”1100”  
3
1st  
1st  
Support byten = ”1000”  
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2.6 FIFO Operation During Card Read Operation  
2.6.1  
EDMA Reads  
The FIFO controller manages the activities of reading the data in from the card and issuing EDMA read  
events. Each time an EDMA read event is issued, an EDMA read request interrupt generates.  
Figure 10 provides details of the FIFO controllers operation. As data is received from the card, it is read  
into the FIFO. When the number of bytes of data received is equal to the level set by the FIFOLEV bits in  
MMCFIFOCTL, an EDMA read event is issued and new EDMA events are disabled until the EDMA is  
done with the transfer issued by the current event. Data is read from the FIFO by way of MMCDRR. The  
FIFO controller continues to read in data from the card while checking for the EDMA event to occur or for  
the FIFO to become full. Once the EDMA event finishes, new EDMA events are enabled. If the FIFO fills  
up, the FIFO controller stops the MMC/SD controller from reading any more data until the FIFO is no  
longer full.  
An EDMA read event generates when the last data arrives, as determined by the MMC block length  
register (MMCBLEN) and the MMC number of blocks register (MMCNBLK) settings. This EDMA event  
flushes all of the data that was read from the card from the FIFO.  
Each time an EDMA read event generates, an interrupt (DRRDYINT) generates and the DRRDY bit in the  
MMC status register 0 (MMCST0) is also set.  
2.6.2  
CPU Reads  
The system CPU can also directly read the card data by reading the MMC data receive register  
(MMCDRR). The MMC/SD peripheral supports reads that are 1, 2, 3, or 4 bytes wide as, shown in  
Figure 8 and Figure 9.  
As data is received from the card, it is read into the FIFO. When the number of bytes of data received is  
equal to the level set by the FIFOLEV bits in MMCFIFOCTL, a DRRDYINT interrupt is issued and the  
DRRDY bit in the MMC status register 0 (MMCST0) is set. Upon receiving the interrupt, the CPU quickly  
reads out the bytes received (equal to the level set by the FIFOLEV bits). A DRRDYINT interrupt also  
generates when the last data arrives as determined by the MMC block length register (MMCBLEN) and  
the MMC numbers of blocks register (MMCNBLK) settings.  
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Figure 10. FIFO Operation During Card Read Diagram  
FIFO Check1/Start  
FIFO  
full  
?
Yes  
No  
Capture data,  
no DMA pending  
Increment counter  
No  
Counter  
=FIFOLEV  
?
Yes  
Generate DMA  
Reset counter  
FIFO check 2  
FIFO  
full  
?
Yes  
No  
Capture data,  
DMA  
Increment counter  
Idle, DMA pending  
Counter  
=FIFOLEV  
?
Yes  
DMA  
done  
?
No  
No  
Yes  
DMA  
done  
?
Generate DMA  
No  
Reset counter  
Yes  
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2.7 FIFO Operation During Card Write Operation  
2.7.1  
EDMA Writes  
The FIFO controller manages the activities of accepting data from the CPU or EDMA and passing the data  
to the MMC/SD controller. The FIFO controller issues EDMA write events as appropriate. Each time an  
EDMA write event is issued, an EDMA write request interrupt generates. Data is written into the FIFO  
through MMCDXR. Note that the EDMA access to MMCDXR is transparent.  
Figure 11 provides details of the FIFO controller's operation. The CPU or EDMA controller writes data into  
the FIFO. The FIFO passes the data to the MMC/SD controller which manages writing the data to the  
card. When the number of bytes of data in the FIFO is less than the level set by the FIFOLEV bits in  
MMCFIFOCTL, an EDMA write event is issued and new EDMA events are disabled. The FIFO controller  
continues to transfer data to the MMC/SD controller while checking for the EDMA event to finish or for the  
FIFO to become empty. Once the EDMA event finishes, new EDMA events are enabled. If the FIFO  
becomes empty, the FIFO controller informs the MMC/SD controller.  
Each time an EDMA write event generates, an interrupt (DXRDYINT) generates and the DXRDY bit in the  
MMC status register 0 (MMCST0) is also set.  
2.7.2  
CPU Writes  
The system CPU can also directly write the card data by writing the MMC data transmit register  
(MMCDXR). The MMC/SD peripheral supports writes that are 1, 2, 3, or 4 bytes wide, as shown in  
Figure 8 and Figure 9.  
The CPU makes use of the FIFO to transfer data to the card via the MMC/SD controller. The CPU writes  
the data to be transferred into MMCDXR. As is the case with the EDMA driven transaction, when the  
number of data in the FIFO is less than the level set by the FIFOLEV bits in MMCFIFOCTL, a DXRDYINT  
interrupt generates and the DXRDY bit in the MMC status register 0 (MMCST0) is set to signify to the  
CPU that space is available for new data.  
Note: When starting the write transaction, the CPU is responsible for getting the FIFO ready to  
start transferring data by filling up the FIFO with data prior to invoking/posting the write  
command to the card. Filling up the FIFO is a requirement since no interrupt/event  
generates at the start of the write transfer.  
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Figure 11. FIFO Operation During Card Write Diagram  
FIFO Check1/Start  
FIFO  
full  
?
Yes  
No  
Capture data,  
no DMA pending  
Increment counter  
No  
Counter  
=FIFOLEV  
?
Yes  
Generate DMA  
Reset counter  
FIFO check 2  
FIFO  
full  
?
Yes  
No  
Capture data,  
DMA  
Increment counter  
Idle, DMA pending  
Counter  
=FIFOLEV  
?
Yes  
DMA  
done  
?
No  
No  
Yes  
DMA  
done  
?
Generate DMA  
No  
Reset counter  
Yes  
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2.8 Reset Considerations  
The MMC/SD peripheral has two reset sources: hardware reset and software reset.  
2.8.1  
2.8.2  
Software Reset Considerations  
A software reset (such as a reset that the emulator generates) does not cause the MMC/SD controller  
registers to alter. After a software reset, the MMC/SD controller continues to operate as it was configured  
prior to the reset.  
Hardware Reset Considerations  
A hardware reset of the processor causes the MMC/SD controller registers to return to their default values  
after reset.  
2.9 Initialization  
2.9.1  
MMC/SD Controller Initialization  
The general procedure for initializing the MMC/SD controller is given in the following steps. Details about  
the registers or register bit fields to be configured in the MMC/SD mode are in the subsequent  
subsections.  
1. Place the MMC/SD controller in its reset state by setting the CMDRST bit and DATRST bit in the MMC  
control register (MMCCTL). You can set other bits in MMCCTL after reset.  
2. Write the required values to other registers to complete the MMC/SD controller configuration.  
3. Clear the CMDRST bit and the DATRST bit in MMCCTL to release the MMC/SD controller from its  
reset state. It is recommended not to rewrite the values that are written to the other bits of MMCCTL in  
Step 1.  
4. Enable the SD_CLK pin so that the memory clock is sent to the memory card by setting the CLKEN bit  
in the MMC memory clock control register (MMCCLK).  
Note: The MMC/SD cards require a clock frequency of 400 kHz or less for the card initialization  
procedure. Make sure that the memory clock confirms this requirement. Once card  
initialization completes, you can adjust the memory clock up to the lower of the card  
capabilities or the maximum frequency that is supported.  
2.9.2  
Initializing the MMC Control Register (MMCCTL)  
The bits in the MMC control register (MMCCTL) affect the operation of the MMC/SD controller. The  
subsections that follow help you decide how to initialize each of control register bits.  
In the MMC/SD mode, the MMC/SD controller must know how wide the data bus must be for the memory  
card that is connected. If an MMC card is connected, specify a 1-bit data bus (WIDTH = 0 in MMCCTL); if  
an SD card is connected, specify a 4-bit data bus (WIDTH = 1 in MMCCTL).  
To place the MMC/SD controller in its reset state and disable it, set the CMDRST bit and DATRST bit in  
MMCCTL. The first step of the MMC/SD controller initialization process is to disable both sets of logic.  
When initialization is complete, but before you enable the SD_CLK pin, clear the CMDRST bit and  
DATRST bit in MMCCTL to enable the MMC/SD controller.  
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2.9.3  
Initializing the Clock Controller Registers (MMCCLK)  
A clock divider in the MMC/SD controller divides-down the function clock to produce the memory clock.  
Load the divide-down value into the CLKRT bits in the MMC memory clock control register (MMCCLK).  
The divide-down value is determined by the following equation:  
memory clock frequency = function clock frequency/(2 × (CLKRT + 1))  
The CLKEN bit in MMCCLK determines whether the memory clock appears on the SD_CLK pin. If you  
clear the CLKEN to 0, the memory clock is not provided except when required.  
2.9.4  
2.9.5  
Initialize the Interrupt Mask Register (MMCIM)  
The bits in the MMC interrupt mask register (MMCIM) individually enable or disable the interrupt requests.  
To enable the associated interrupt request, set the corresponding bit in MMCIM. To disable the associated  
interrupt request, clear the corresponding bit. Load zeros into the bits that are not used in the MMC/SD  
mode.  
Initialize the Time-Out Registers (MMCTOR and MMCTOD)  
Specify the time-out period for responses using the MMC response time-out register (MMCTOR) and the  
time-out period for reading data using the MMC data read time-out register (MMCTOD).  
When the MMC/SD controller sends a command to a memory card, it must often wait for a response. The  
MMC/SD controller can wait indefinitely or up to 255 memory clock cycles. If you load 0 into MMCTOR,  
the MMC/SD controller waits indefinitely for a response. If you load a nonzero value into MMCTOR, the  
MMC/SD controller stops waiting after the specified number of memory clock cycles and then sets a  
response time-out flag (TOUTRS) in the MMC status register 0 (MMCST0). If you enable the associated  
interrupt request, the MMC/SD controller also sends an interrupt request to the ARM.  
When the MMC/SD controller requests data from a memory card, it can wait indefinitely for that data or it  
can stop waiting after a programmable number of cycles. If you load 0 into MMCTOD, the MMC/SD  
controller waits indefinitely. If you load a nonzero value into MMCTOD, the MMC/SD controller waits the  
specified number of memory clock cycles and then sets a read data time-out flag (TOUTRD) in MMCST0.  
If you enable the associated interrupt request, the MMC/SD controller also sends an interrupt request to  
the ARM.  
2.9.6  
Initialize the Data Block Registers (MMCBLEN and MMCNBLK)  
Specify the number of bytes in a data block in the MMC block length register (MMCBLEN) and the number  
of blocks in a multiple-block transfer in the MMC number of blocks register (MMCNBLK).  
You must define the size for each block of data transferred between the MMC/SD controller and a memory  
card in MMCBLEN. The valid size depends on the type of read/write operations. A length of 0 bytes is  
prohibited.  
For multiple-block transfers, you must specify how many blocks of data are to be transferred between the  
MMC/SD controller and a memory card. You can specify an infinite number of blocks by loading 0 into  
MMCNBLK. When MMCNBLK = 0, the MMC/SD controller continues to transfer data blocks until the  
transferring is stopped with a STOP_TRANSMISSION command. To transfer a specific number of blocks,  
load MMCNBLK with a value from 1 to 65 535.  
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2.9.7  
Monitoring Activity in the MMC/SD Mode  
This section describes registers and specific register bits that you can use to obtain the status of the  
MMC/SD controller in the MMC/SD mode. You can determine the status of the MMC/SD controller by  
reading the bits in the MMC status register 0 (MMCST0) and MMC status register 1 (MMCST1).  
2.9.7.1  
Determining Whether New Data is Available in MMCDRR  
The MMC/SD controller sets the DRRDY bit in MMCST0 when the data in the FIFO is greater than the  
threshold set in the MMC FIFO control register (MMCFIFOCTL). If the interrupt request is enabled  
(EDRRDY = 1 in MMCIM), the ARM is notified of the event by an interrupt. A read of the MMC data  
receive register (MMCDDR) clears the DRRDY flag.  
2.9.7.2  
Verifying that MMCDXR is Ready to Accept New Data  
The MMC/SD controller sets the DXRDY bit in MMCST0 when the amount of data in the FIFO is less than  
the threshold set in the MMC FIFO control register (MMCFIFOCTL). If the interrupt request is enabled  
(EDXRDY = 1 in MMCIM), the ARM is notified of the event by an interrupt.  
2.9.7.3  
Checking for CRC Errors  
The MMC/SD controller sets the CRCRS, CRCRD, and CRCWR bits in MMCST0 in response to the  
corresponding CRC errors of command response, data read, and data write. If the interrupt request is  
enabled (ECRCRS/ECRCRD/ECRCWR = 1 in MMCIM), the ARM is notified of the CRC error by an  
interrupt.  
2.9.7.4  
2.9.7.5  
2.9.7.6  
Checking for Time-Out Events  
The MMC/SD controller sets the TOUTRS and TOUTRD bits in MMCST0 in response to the  
corresponding command response or data read time-out event. If the interrupt request is enabled  
(ETOUTRS/ETOUTRD = 1 in MMCIM), the ARM is notified of the event by an interrupt.  
Determining When a Response/Command is Done  
The MMC/SD controller sets the RSPDNE bit in MMCST0 when the response is done; or in the case of  
commands that do not require a response, when the command is done. If the interrupt request is enabled  
(ERSPDNE = 1 in MMCIM), the ARM is also notified.  
Determining Whether the Memory Card is Busy  
The card sends a busy signal either when waiting for an R1b-type response or when programming the last  
write data into its flash memory. The MMC/SD controller has two flags to notify you whether the memory  
card is sending a busy signal. The two flags are complements of each other:  
The BSYDNE flag in MMCST0 is set if the card did not send or is not sending a busy signal when the  
MMC/SD controller is expecting a busy signal (BSYEXP = 1 in MMCCMD). The interrupt by this bit is  
enabled by a corresponding interrupt enable bit (EBSYDNE = 1 in MMCIM).  
The BUSY flag in MMCST1 is set when a busy signal is received from the card.  
2.9.7.7  
Determining Whether a Data Transfer is Done  
The MMC/SD controller sets the DATDNE bit in MMCST0 when all of the bytes of a data transfer have  
been transmitted/received. The DATDNE bit is polled to determine when to stop writing to the data  
transmit register (for a write operation) or when to stop reading from the data receive register (for a read  
operation). The ARM is also notified of the time-out event by an interrupt if the interrupt request is enabled  
(EDATDNE = 1 in MMCIM).  
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2.9.7.8  
Determining When Last Data has Been Written to Card (SanDisk SD cards)  
Some SanDisk brand SD™ cards exhibit a behavior that requires a multiple-block write command to  
terminate with a STOP (CMD12) command before the data write sequence completes. To enable support  
of this function, the transfer done interrupt (TRNDNE) is provided. Set the ETRNDNE bit in MMCIM to  
enable the TRNDNE interrupt. This interrupt is issued when the last byte of data (as defined by  
MMCNBLK and MMCBLEN) is transferred from the FIFO to the output shift register. The CPU should  
respond to this interrupt by sending a STOP command to the card. This interrupt differs from DATDNE by  
timing. DATDNE does not occur until after the CRC and memory programming are complete.  
2.9.7.9  
Checking For a Data Transmit Empty Condition  
During transmission, a data value is passed from the MMC data transmit register (MMCDXR) to the data  
transmit shift register. The data is then passed from the shift register to the memory card one bit at a time.  
The DXEMP bit in MMCST1 indicates when the shift register is empty.  
Typically, the DXEMP bit is not used to control data transfers; rather, it is checked during recovery from an  
error condition. There is no interrupt associated with the DXEMP bit.  
2.9.7.10 Checking for a Data Receive Full Condition  
During reception, the data receive shift register accepts a data value one bit at a time. The entire value is  
then passed from the shift register to the MMC data receive register (MMCDRR). The DRFUL bit in  
MMCST1 indicates that when the shift register is full no new bits can be shifted in from the memory card.  
The DRFUL bit is not typically used to control data transfers; rather, it is checked during recovery from an  
error condition. There is no interrupt associated with the DRFUL bit.  
2.9.7.11 Checking the Status of the SD_CLK Pin  
Read the CLKSTP bit in MMCST1 to determine whether the memory clock has been stopped on the  
SD_CLK pin.  
2.9.7.12 Checking the Remaining Block Count During a Multiple-Block Transfer  
During a transfer of multiple data blocks, the MMC number of blocks counter register (MMCNBLC)  
indicates how many blocks are remaining to be transferred. The MMCNBLC is a read-only register.  
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2.10 Interrupt Support  
2.10.1 Interrupt Events and Requests  
The MMC/SD controller generates the interrupt requests described in Table 4. When an interrupt event  
occurs, its flag bit is set in the MMC status register 0 (MMCST0). If the enable bits corresponding to each  
flag are set in the MMC interrupt mask register (MMCIM), an interrupt request generates. All such  
requests are multiplexed to a single MMC/SD interrupt request from the MMC/SD peripheral to the ARM  
CPU.  
The MMC/SD interrupts are part of the maskable ARM interrupts. The ARM interrupt 26 (INT26) is  
associated with MMC functions and the ARM interrupt 27 (INT27) is associated with SD functions. The  
interrupt service routine (ISR) for the MMC/SD interrupt can determine the event that caused the interrupt  
by checking the bits in MMCST0. When MMCST0 is read, all register bits automatically clear. During a  
middle of data transfer, the DXRDY and DRRDY bits are set during every 128-byte or 256-byte transfer,  
depending on the the MMC FIFO control register (MMCFIFOCTL) setting. Performing a write and a read in  
response to the interrupt generated by the FIFO automatically clears the corresponding interrupt bit/flag.  
Note: You must be aware that an emulation read of the status register clears the interrupt status  
flags. To avoid inadvertently clearing the flag, be careful while monitoring MMCST0 via  
the debugger.  
2.10.2 Interrupt Multiplexing  
The interrupts from the MMC/SD peripheral to the ARM CPU are not multiplexed with any other interrupt  
source.  
Table 4. Description of MMC/SD Interrupt Requests  
Interrupt  
Request  
Interrupt Event  
TRNDNEINT  
For read operations: The MMC/SD controller has received the last byte of data (before CRC check).  
For write operations: The MMC/SD controller has transferred the last word of data to the output shift register.  
An edge was detected on the DAT3 pin.  
DATEDINT  
DRRDYINT  
DXRDYINT  
CRCRSINT  
CRCRDINT  
CRCWRINT  
TOUTRSINT  
TOUTRDINT  
RSPDNEINT  
MMCDRR is ready to be read (data in FIFO is above threshold).  
MMCDXR is ready to transmit new data (data in FIFO is less than threshold).  
A CRC error was detected in a response from the memory card.  
A CRC error was detected in the data read from the memory card.  
A CRC error was detected in the data written to the memory card.  
A time-out occurred while the MMC controller was waiting for a response to a command.  
A time-out occurred while the MMC controller was waiting for the data from the memory card.  
For a command that requires a response: The MMC controller has received the response without a CRC error.  
For a command that does not require a response: The MMC controller has finished sending the command.  
The memory card stops or is no longer sending a busy signal when the MMC controller is expecting a busy signal.  
For read operations: The MMC controller has received data without a CRC error.  
For write operations: The MMC controller has finished sending data.  
BSYDNEINT  
DATDNEINT  
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2.11 DMA Event Support  
The MMC/SD controller is capable of generating EDMA events for both read and write operations in order  
to request service from an EDMA controller. Based on the FIFO threshold setting, the EDMA event signals  
generate every time 128-bit or 256-bit data is transferred from the FIFO.  
2.12 Power Management  
You can put the MMC/SD peripheral in reduced-power modes to conserve power during periods of low  
activity. The processor power and sleep controller (PSC) controls the power management of the MMC/SD  
peripheral. The PSC acts as a master controller for power management for all of the peripherals on the  
device. For detailed information on power management procedures using the PSC, see the  
TMS320DM644x DMSoC ARM Subsystem Reference Guide (SPRUE14).  
2.13 Emulation Considerations  
The MMC/SD peripheral is not affected by emulation halt events (such as breakpoints).  
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Procedures for Common Operations  
3
Procedures for Common Operations  
3.1 Card Identification Operation  
Before the MMC/SD controller starts data transfers to or from memory cards in the MMC/SD native mode,  
it must first identify how many cards are present on the bus and configure them. For each card that  
responds to the ALL_SEND_CID broadcast command, the controller reads that card’s unique card  
identification address (CID) and then assigns it a relative address (RCA). This address is much shorter  
than the CID and the MMC/SD controller uses this address to identify the card in all future commands that  
involve the card.  
Only one card completes the response to ALL_SEND_CID at any one time. The absence of any response  
to ALL_SEND_CID indicates that all cards have been identified and configured.  
Note: The following steps assume that the MMC/SD controller is configured to operate in MMC  
or SD mode, and the memory clock frequency on the CLK pin is set for 400 kHz or less.  
The procedure for a card identification operation is issued in open-drain bus mode for both MMC and SD  
cards.  
3.1.1  
MMC Card Identification Procedure  
The MMC card identification procedure is:  
1. Use the MMC command register (MMCCMD) to issue the GO_IDLE_STATE (CMD0) command to the  
MMC cards. Using MMCCMD to issue the CMD0 command puts all cards (MMC and SD) in the idle  
state and no response from the cards is expected.  
2. Use MMCCMD to issue the SEND_OP_CMD (CMD1) command with the voltage range supported (R3  
response, if it is successful; R1b response, if the card is expected to be busy). Using MMCCMD to  
issue the CMD1 command allows the host to identify and reject cards that do not match the VDD  
range that the host supports.  
3. If the response in step 2 is R1b (that is, the card is still busy due to power up), then go back to step 2.  
If the card is not busy, continue to step 4.  
4. Use MMCCMD to send the ALL_SEND_CID (CMD2) command (R2 response is expected) to the MMC  
cards. Using MMCCMD to send the CMD2 command notifies all cards to send their unique card  
identification (CID) number. There should only be one card that successfully sends its full CID number  
to the host. The successful card goes into the identification state and does not respond to this  
command again.  
5. Use MMCMD to issue the SET_RELATIVE_ADDR (CMD3) command (R1 response is expected) in  
order to assign an address that is shorter than the CID number that will be used in the future to  
address the card in the future data transfer mode.  
Note: This command is only addressed to the card that successfully sent its CID number in  
step 4. This card now goes into standby mode. This card also changes its output drivers  
from open-drain to push-pull. It stops replying to the CMD2 command, allowing for the  
identification of other cards.  
6. Repeat step 4 and step 5 to identify and assign relative addresses to all remaining cards until no card  
responds to the CMD1 command. No card responding within 5 memory clock cycles indicates that all  
cards have been identified and the MMC card identification procedure terminates.  
The sequence of events in this operation is shown in Figure 12.  
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Figure 12. MMC Card Identification Procedure  
3.1.2  
SD Card Identification Procedure  
The SD card identification procedure is:  
1. Use the MMC command register (MMCCMD) to issue the GO_IDLE_STATE (CMD0) command to the  
MMC cards. Using MMCMD to issue the CMD0 command puts all cards (MMC and SD) in the idle  
state and no response from the cards is expected.  
2. Use MMCCMD to issue the APP_CMD (CMD55) command (R1 response is expected) to indicate that  
the command that follows is an application command.  
3. Use MMCCMD to send the SD_SEND_OP_COND (ACMD41) command with the voltage range  
supported (R3 response is expected) to SD cards. Using MMCCMD to send the ACMD41 command  
allows the host to identify and reject cards that do not match the VDD range that the host supports.  
4. Use MMCCMD to send the ALL_SEND_CID (CMD2) command (R2 response is expected) to the MMC  
cards. Using MMCCMD to send the CMD2 command notifies all cards to send their unique card  
identification (CID) number. There should only be one card that successfully sends its full CID number  
to the host. The successful card goes into identification state and does not respond to this command  
again.  
5. Use MMCMD to issue the SEND_RELATIVE_ADDR (CMD3) command (R1 response is expected) in  
order to ask the card to publish a new relative address for future use to address the card in data  
transfer mode.  
Note: This command is only addressed to the card that successfully sent its CID number in  
step 4. This card now goes into standby mode. This card also changes its output drivers  
from open-drain to push-pull. It stops replying to the CMD2 command, allowing for the  
identification of other cards.  
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6. Repeat step 4 and step 5 to identify and retrieve relative addresses from all remaining SD cards until  
no card responds to the CMD2 command. No card responding within 5 memory clock cycles indicates  
that all cards have been identified and the MMC card and the identification procedure terminates.  
The sequence of events in this operation is shown in Figure 13.  
Figure 13. SD Card Identification Procedure  
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3.2 MMC/SD Mode Single-Block Write Operation Using CPU  
To perform a single-block write, the block length must be 512 bytes and the same length needs to be set  
in both the MMC/SD controller and the memory card. The procedure for this operation is:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the higher part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Use the MMC command register (MMCCMD) to send the SELECT/DESELECT_CARD broadcast  
command. This selects the addressed card and deselects the others.  
3. Write the destination start address to the MMC argument registers. Load the high part to the  
MMCARGH register and the low part to MMCARGL.  
4. Read the card CSD to determine the card’s maximum block length.  
5. Use MMCCMD to send the SET_BLOCKLEN command (if the block length is different than the length  
used in the previous operation). The block length must be a multiple of 512 bytes and less then the  
maximum block length specified in the CSD.  
6. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
7. Set the FIFO direction to transmit (FIFODIR bit in MMCFIFOCTL).  
8. Set the access width (ACCWD bits in MMCFIFOCTL).  
9. Enable the MMC interrupt.  
10. Enable the DXRDYINT interrupt.  
11. Write the first 32 bytes of the data block to the data transmit register (MMCDXR).  
12. Use MMCCMD to send the WRITE_BLOCK command to the card.  
13. Wait for the MMC interrupt.  
14. Use the MMC status register 0 (MMCST0) to check for errors and the status of the FIFO. If all of the  
data has not been written and if the FIFO is not full, go to step 15. If all of the data has been written,  
stop.  
15. Write the next n bytes (this depends on the setting of the FIFOLEV bit in MMCFIFOCTL: 0 = 16 bytes,  
1 = 32 bytes) of the data block to the MMC data transmit register (MMCDXR) and go to step 13.  
The sequence of events in this operation is shown in Figure 14.  
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Figure 14. MMC/SD Mode Single-Block Write Operation  
MMC controller  
register content  
MMC controller  
register  
RCA ADDRESS HIGH  
RCA ADDRESS LOW  
SEL/DESEL. CARD  
ARG HIGH  
ARG LOW  
COMMAND  
Select one card with relative  
card address (RCA) while  
de−selecting the other cards  
BLK ADDRESS HIGH  
BLK ADDRESS LOW  
FIRST DATA BYTE  
WRITE BLOCK  
ARG HIGH  
ARG LOW  
DATA TX  
Load starting block address  
into the high and low argument  
registers. Load the first byte of  
the transfer. Start writing one  
block of data. Only 512 byte  
block length is permitted.  
COMMAND  
Is CRCWR = 1?  
Is DATDNE = 1?  
Is DXRDY = 1?  
Check CRCWR bit for any  
write CRC errors.  
Check DATDNE bit to see if the  
transfer is done. If not, then...  
Check DXRDY bit to see the  
data transmit register is ready  
for the next byte.  
STATUS 0  
DATA TX  
NEXT DATA BYTE  
Load the data transmit register  
with the next byte.  
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3.3 MMC/SD Mode Single-Block Write Operation Using the EDMA  
To perform a single-block write, the block length must be 512 bytes and the same length must be set in  
both the MMC/SD controller and the card.  
The procedure for this operation is as follows:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Read the card CSD to determine the card's maximum block length.  
3. Use the MMC command register (MMCCMD) to send the SET_BLOCKLEN command (if the block  
length is different than the length used in the previous operation). The block length must be a multiple  
of 512 bytes and less then the maximum block length specified in the CSD.  
4. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
5. Set the FIFO direction to transmit (FIFODIR bit in MMCFIFOCTL).  
6. Set the access width (ACCWD bits in MMCFIFOCTL).  
7. Set the FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
8. Set up the DMA (DMA size must be greater than or equal to the FIFOLEV setting).  
9. Use MMCCMD to send the WRITE _BLOCK command to the card (set the DMATRIG bit in MMCCMD  
to trigger the first DMA).  
10. Wait for the DMA sequence to complete or for the DATADNE flag in the MMC status register 0  
(MMCST0) to be set.  
11. Use MMCST0 to check for errors.  
3.4 MMC/SD Mode Single-Block Read Operation Using the CPU  
To perform a single-block read, the same block length must be set in both the MMC/SD controller and the  
card.  
The procedure for this operation is as follows:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MCARGH and the low part of the address to MMCARGL.  
2. Use the MMC command register (MMCCMD) to send the SELECT/DESELECT_CARD broadcast  
command. This selects the addressed card and deselects the others.  
3. Write the source start address to the MMC argument registers. Load the high part to MMCARGH and  
the low part to MMCARGL.  
4. Read card CSD to determine the card's maximum block length.  
5. Use MMCCMD to send the SET_BLOCKLEN command (if the block length is different than the length  
used in the previous operation). The block length must be a multiple of 512 bytes and less then the  
maximum block length specified in the CSD.  
6. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
7. Set the FIFO direction to receive (FIFODIR bit in MMCFIFOCTL).  
8. Set the access width (ACCWD bits in MMCFIFOCTL).  
9. Set the FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
10. Enable the MMC interrupt.  
11. Enable the DRRDYINT interrupt.  
12. Use MMCCMD to send the READ_SINGLE_BLOCK command.  
13. Wait for the MMC interrupt.  
14. Use the MMC status register 0 (MMCST0) to check for errors and the status of the FIFO. If the FIFO is  
not empty, go to step 15. If the all of the data has been read, stop.  
15. Read the next n bytes of data (this depends on the setting of the FIFOLEV bit in MMCFIFOCTL:  
0 = 16 bytes, 1 = 32 bytes) from the MMC data receive register (MMCDRR) and go to step 13.  
The sequence of events in this operation is shown in Figure 15.  
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Figure 15. MMC/SD Mode Single-Block Read Operation  
MMC controller  
register content  
MMC controller  
register  
RCA ADDRESS HIGH  
RCA ADDRESS LOW  
SEL/DESEL. CARD  
ARG HIGH  
ARG LOW  
COMMAND  
Select one card with relative  
card address (RCA) while  
de−selecting the other cards.  
BLK ADDRESS HIGH  
BLK ADDRESS LOW  
SET_BLOCKLEN  
ARG HIGH  
ARG LOW  
COMMAND  
COMMAND  
Load starting block address  
into the high and low argument  
registers. Load block  
length register. Start the  
operation by loading a  
READ_SINGLE_BLOCK  
command into the command  
register.  
READ_SINGLE_BLOCK  
Is CRCWR = 1?  
Is DXRDY = 1?  
Check CRCWR bit for any write  
CRC errors.  
Check DXRDY to see if a new  
byte can be put in MMCDXR  
register.  
STATUS 0  
DATA TX  
NEXT DATA BYTE  
STOP_TRANSMISSION  
Terminate the multiple−block  
write operation.  
COMMAND  
3.5 MMC/SD Mode Single-Block Read Operation Using EDMA  
To perform a single-block read, the same block length needs to be set in both the MMC/SD controller and  
the card. The procedure for this operation is:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Read card CSD to determine the card's maximum block length.  
3. Use the MMC command register (MMCCMD) to send the SET_BLOCKLEN command (if the block  
length is different than the length used in the previous operation). The block length must be a multiple  
of 512 bytes and less then the maximum block length specified in the CSD.  
4. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
5. Set the FIFO direction to receive (FIFODIR bit in MMCFIFOCTL).  
6. Set the access width (ACCWD bits in MMCFIFOCTL).  
7. Set the FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
8. Set up DMA (DMA size needs to be greater than or equal to FIFOLEV setting).  
9. Use MMCCMD to send the READ _BLOCK command to the card.  
10. Wait for DMA sequence to complete.  
11. Use the MMC status register 0 (MMCST0) to check for errors.  
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3.6 MMC/SD Mode Multiple-Block Write Operation Using CPU  
To perform a multiple-block write, the same block length needs to be set in both the MMC/SD controller  
and the card.  
Note: The procedure in this section uses a STOP_TRANSMISSION command to end the block transfer.  
This assumes that the value in the MMC number of blocks counter register (MMCNBLK) is 0. A  
multiple-block operation terminates itself if you load MMCNBLK with the exact number of blocks you want  
transferred.  
The procedure for this operation is:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Read card CSD to determine the card's maximum block length.  
3. Use the MMC command register (MMCCMD) to send the SET_BLOCKLEN command (if the block  
length is different than the length used in the previous operation). The block length must be a multiple  
of 512 bytes and less then the maximum block length specified in the CSD.  
4. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
5. Set the FIFO direction to transmit (FIFODIR bit in MMCFIFOCTL).  
6. Set the access width (ACCWD bits in MMCFIFOCTL).  
7. Set the FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
8. Enable the MMC interrupt.  
9. Enable DXRDYINT interrupt.  
10. Write the first 32 bytes of the data block to the MMC data transmit register (MMCDXR).  
11. Use MMCCMD to send the WRITE_MULTI_BLOCK command to the card.  
12. Wait for MMC interrupt.  
13. Use the MMC status register 0 (MMCST0) to check for errors and to determine the status of the FIFO.  
If more bytes are to be written and the FIFO is not full, go to step 14. If the all of the data has been  
written, go to step 15.  
14. Write the next n bytes (depends on setting of FIFOLEV in MMCFIFOCTL: 0 = 16 bytes, 1 = 32 bytes)  
of the data block to MMCDXR, and go to step 12.  
15. Use MMCCMD to send the STOP_TRANSMISSION command.  
The sequence of events in this operation is shown in Figure 16.  
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Figure 16. MMC/SD Multiple-Block Write Operation  
MMC controller  
register content  
MMC controller  
register  
RCA ADDRESS HIGH  
RCA ADDRESS LOW  
SEL/DESEL. CARD  
ARG HIGH  
ARG LOW  
COMMAND  
Select one card with relative  
card address (RCA) while  
de−selecting the other cards.  
BLK ADDRESS HIGH  
BLK ADDRESS LOW  
SET_BLOCKLEN  
ARG HIGH  
ARG LOW  
COMMAND  
COMMAND  
Load starting block address  
into the high and low argument  
registers. Load block  
length register. Start the  
operation by loading a  
READ_SINGLE_BLOCK  
command into the command  
register.  
READ_SINGLE_BLOCK  
Is CRCWR = 1?  
Is DXRDY = 1?  
Check CRCWR bit for any write  
CRC errors.  
Check DXRDY to see if a new  
byte can be put in MMCDXR  
register.  
STATUS 0  
DATA TX  
NEXT DATA BYTE  
STOP_TRANSMISSION  
Terminate the multiple−block  
write operation.  
COMMAND  
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3.7 MMC/SD Mode Multiple-Block Write Operation Using EDMA  
To perform a multiple-block write, the same block length needs to be set in both the MMC/SD controller  
and the card. The procedure for this operation is:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Read card CSD to determine the card's maximum block length.  
3. Use the MMC command register (MMCCMD) to send the SET_BLOCKLEN command (if the block  
length is different than the length used in the previous operation). The block length must be a multiple  
of 512 bytes and less then the maximum block length specified in the CSD.  
4. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
5. Set the FIFO direction to transmit (FIFODIR bit in MMCFIFOCTL).  
6. Set the FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
7. Set the access width (ACCWD bits in MMCFIFOCTL).  
8. Set up DMA (DMA size needs to be greater than or equal to FIFOLEV setting).  
9. Use MMCCMD to send the WRITE_MULTI_BLOCK command to the card (set DMATRIG bit in  
MMCCMD to trigger first DMA).  
10. Wait for DMA sequence to complete or the DATADNE flag in the MMC status register 0 (MMCST0) is  
set.  
11. Use MMCST0 to check for errors.  
12. Use MMCCMD to send the STOP_TRANSMISSION command.  
3.8 MMC/SD Mode Multiple-Block Read Operation Using CPU  
To perform a multiple-block read, the same block length needs to be set in both the MMC/SD controller  
and the card.  
Note: The procedure in this section uses a STOP_TRANSMISSION command to end the block transfer.  
This assumes that the value in the MMC number of blocks counter register (MMCNBLK) is 0. A  
multiple-block operation terminates itself if you load MMCNBLK with the exact number of blocks you want  
transferred.  
The procedure for this operation is:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Read card CSD to determine the card's maximum block length.  
3. Use the MMC command register (MMCCMD) to send the SET_BLOCKLEN command (if the block  
length is different than the length used in the previous operation). The block length must be a multiple  
of 512 bytes and less then the maximum block length specified in the CSD.  
4. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
5. Set the FIFO direction to receive (FIFODIR bit in MMCFIFOCTL).  
6. Set FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
7. Set the access width (ACCWD bits in MMCFIFOCTL).  
8. Enable the MMC interrupt.  
9. Enable DRRDYINT interrupt.  
10. Use MMCCMD to send the READ_MULT_BLOCKS command.  
11. Wait for MMC interrupt.  
12. Use the MMC status register 0 (MMCST0) to check for errors and to determine the status of the FIFO.  
If FIFO is not empty and more bytes are to be read, go to step 13. If the all of the data has been read,  
go to step 14.  
13. Read n bytes (depends on setting of FIFOLEV in MMCFIFOCTL: 0 = 16 bytes, 1 = 32 bytes) of data  
from the MMC data receive register (MMCDRR) and go to step 10.  
14. Use MMCCMD to send the STOP_TRANSMISSION command.  
The sequence of events in this operation is shown in Figure 17.  
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Figure 17. MMC/SD Mode Multiple-Block Read Operation  
MMC controller  
register content  
MMC controller  
register  
RCA ADDRESS HIGH  
RCA ADDRESS LOW  
SEL/DESEL. CARD  
ARG HIGH  
ARG LOW  
COMMAND  
Select one card with relative  
card address (RCA) while  
de−selecting the other cards.  
BLK ADDRESS HIGH  
BLK ADDRESS LOW  
SET_BLOCKLEN  
ARG HIGH  
ARG LOW  
COMMAND  
COMMAND  
Load starting block address  
into the high and low argument  
registers. Load block  
length register with the block  
length value. Start the operation by  
loading a READ_MULTIPLE_BLOCK  
command into the command  
register.  
READ_MULT_BLOCK  
Is TOUTRD = 1?  
Is CRCRD = 1?  
Is DRRDY = 1?  
Check TOUTRD bit to verify  
that the read operation has not  
timed−out. Check CRCRD bit for  
any read CRC errors. Check DRRDY  
to see if a new byte is in the data  
receive register.  
STATUS 0  
DATA TX  
NEXT DATA BYTE  
STOP_TRANSMISSION  
Terminate the multiple−block  
read operation.  
COMMAND  
3.9 MMC/SD Mode Multiple-Block Read Operation Using EDMA  
To perform a multiple-block read, the same block length must be set in both the MMC/SD controller and  
the card.  
The procedure for this operation is as follows:  
1. Write the card’s relative address to the MMC argument registers (MMCARGH and MMCARGL). Load  
the high part of the address to MMCARGH and the low part of the address to MMCARGL.  
2. Read card CSD to determine the card's maximum block length.  
3. Use the MMC command register (MMCCMD) to send the SET_BLOCKLEN command (if the block  
length is different than the length used in the previous operation). The block length must be a multiple  
of 512 bytes and less then the maximum block length specified in the CSD.  
4. Reset the FIFO (FIFORST bit in MMCFIFOCTL).  
5. Set the FIFO direction to receive (FIFODIR bit in MMCFIFOCTL).  
6. Set the FIFO threshold (FIFOLEV bit in MMCFIFOCTL).  
7. Set the access width (ACCWD bits in MMCFIFOCTL).  
8. Set up DMA (DMA size needs to be greater than or equal to FIFOLEV setting).  
9. Use MMCCMD to send the READ_MULTI_BLOCK command to the card.  
10. Wait for DMA sequence to complete.  
11. Use the MMC status register 0 (MMCST0) to check for errors.  
12. Use MMCCMD to send the STOP_TRANSMISSION command.  
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Registers  
4
Registers  
Table 5 lists the memory-mapped registers for the multimedia card/secure digital (MMC/SD) card  
controller. See the device-specific data manual for the memory address of these registers.  
Table 5. Multimedia Card/Secure Digital (MMC/SD) Card Controller Registers  
Offset  
00h  
04h  
08h  
0Ch  
10h  
14h  
18h  
1Ch  
20h  
24h  
28h  
2Ch  
30h  
34h  
38h  
3Ch  
40h  
44h  
48h  
50h  
74h  
Acronym  
Register Description  
Section  
MMCCTL  
MMC Control Register  
Section 4.1  
Section 4.2  
Section 4.3  
Section 4.4  
Section 4.5  
Section 4.6  
Section 4.7  
Section 4.8  
Section 4.9  
Section 4.10  
Section 4.11  
Section 4.12  
Section 4.13  
Section 4.14  
Section 4.15  
Section 4.15  
Section 4.15  
Section 4.15  
Section 4.16  
Section 4.17  
Section 4.18  
MMCCLK  
MMC Memory Clock Control Register  
MMC Status Register 0  
MMCST0  
MMCST1  
MMC Status Register 1  
MMCIM  
MMC Interrupt Mask Register  
MMC Response Time-Out Register  
MMC Data Read Time-Out Register  
MMC Block Length Register  
MMC Number of Blocks Register  
MMC Number of Blocks Counter Register  
MMC Data Receive Register  
MMC Data Transmit Register  
MMC Command Register  
MMCTOR  
MMCTOD  
MMCBLEN  
MMCNBLK  
MMCNBLC  
MMCDRR  
MMCDXR  
MMCCMD  
MMCARGHL  
MMCRSP01  
MMCRSP23  
MMCRSP45  
MMCRSP67  
MMCDRSP  
MMCCIDX  
MMCFIFOCTL  
MMC Argument Register  
MMC Response Register 0 and 1  
MMC Response Register 2 and 3  
MMC Response Register 4 and 5  
MMC Response Register 6 and 7  
MMC Data Response Register  
MMC Command Index Register  
MMC FIFO Control Register  
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Registers  
4.1 MMC Control Register (MMCCTL)  
The MMC control register (MMCCTL) is used to enable or configure various modes of the MMC controller.  
Set or clear the DATRST and CMDRST bits at the same time to reset or enable the MMC controller.  
The MMC control register (MMCCTL) is shown in Figure 18 and described in Table 6.  
Figure 18. MMC Control Register (MMCCTL)  
31  
16  
Reserved  
R-0  
15  
7
11  
3
10  
9
8
Reserved  
R-0  
PERMDX  
R/W-0  
PERMDR  
R/W-0  
Reserved  
R-0  
6
5
2
1
0
DATEG  
R/W-0  
Reserved  
R-0  
WIDTH  
R/W-0  
CMDRST  
R/W-0  
DATRST  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 6. MMC Control Register (MMCCTL) Field Descriptions  
Bit  
Field  
Value Description  
31-11 Reserved  
0
Reserved  
10  
9
PERMDX  
PERMDR  
Endian select when writing.  
Little endian is selected.  
0
1
Big endian is selected.  
Endian select when reading.  
Little endian is selected.  
0
1
Big endian is selected.  
8
Reserved  
DATEG  
0
Reserved  
7-6  
0-3h  
0
DAT3 edge detection select.  
DAT3 edge detection is disabled.  
DAT3 rising-edge detection is enabled.  
DAT3 falling-edge detection is enabled.  
DAT3 rising-edge and falling-edge detections are enabled.  
Reserved  
1h  
2h  
3h  
0
5-3  
2
Reserved  
WIDTH  
Data bus width (MMC mode only).  
Data bus has 1 bit (only DAT0 is used).  
Data bus has 4 bits (all DAT0-3 are used).  
CMD logic reset.  
0
1
1
0
CMDRST  
DATRST  
0
1
CMD line portion is enabled.  
CMD line portion is disabled and in reset state.  
DAT logic reset.  
0
1
DAT line portion is enabled.  
DAT line portion is disabled and in reset state.  
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4.2 MMC Memory Clock Control Register (MMCCLK)  
The MMC memory clock control register (MMCCLK) is used to:  
Select whether the CLK pin is enabled or disabled (CLKEN bit).  
Select how much the function clock is divided-down to produce the memory clock (CLKRT bits). When  
the CLK pin is enabled, the MMC controller drives the memory clock on this pin to control the timing of  
communications with attached memory cards. For more details about clock generation, see  
Section 2.1.  
The MMC memory clock control register (MMCCLK) is shown in Figure 19 and described in Table 7.  
Figure 19. MMC Memory Clock Control Register (MMCCLK)  
31  
15  
16  
0
Reserved  
R-0  
9
8
7
Reserved  
R-0  
CLKEN  
R/W-0  
CLKRT  
R/W–FFh  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 7. MMC Memory Clock Control Register (MMCCLK) Field Descriptions  
Bit  
31-9  
8
Field  
Value Description  
Reserved  
CLKEN  
0
Reserved  
CLK pin enable.  
0
1
CLK pin is disabled and fixed low.  
The CLK pin is enabled; it shows the memory clock signal.  
7-0  
CLKRT  
0–FFh Clock rate. Use this field to set the divide-down value for the memory clock. The function clock is  
divided down as follows to produce the memory clock:  
memory clock frequency = function clock frequency/(2 × (CLKRT + 1) )  
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4.3 MMC Status Register 0 (MMCST0)  
The MMC status register 0 (MMCST0) records specific events or errors. The transition from 0 to 1 on each  
bit in MMCST0 can cause an interrupt signal to be sent to the CPU. If an interrupt is desired, set the  
corresponding interrupt enable bit in the MMC interrupt mask register (MMCIM).  
In most cases, when a status bit is read, it is cleared. The two exceptions are the DRRDY bit and the  
DXRDY bit; these bits are cleared only in response to the functional events described for them in Table 8,  
or in response to a hardware reset.  
The MMC status register 0 (MMCST0) is shown in Figure 20 and described in Table 8.  
Figure 20. MMC Status Register 0 (MMCST0)  
31  
16  
Reserved  
R-0  
15  
7
13  
12  
TRNDNE  
R-0  
11  
10  
DRRDY  
R-0  
9
8
Reserved  
R-0  
DATED  
RC-0  
DXRDY  
R-1  
Reserved  
R-0  
6
5
4
3
2
1
0
CRCRS  
R-0  
CRCRD  
R-0  
CRCWR  
R-0  
TOUTRS  
R-0  
TOUTRD  
R-0  
RSPDNE  
R-0  
BSYDNE  
R-0  
DATDNE  
R-0  
LEGEND: R = Read only; RC = Cleared to 0 when read; -n = value after reset  
Table 8. MMC Status Register 0 (MMCST0) Field Descriptions  
Bit  
Field  
Value Description  
31-13 Reserved  
0
Reserved  
12  
11  
10  
TRNDNE  
DATED  
DRRDY  
Transfer done.  
0
1
No data transfer is done.  
Data transfer of specified length is done.  
DAT3 edge detected. DATED is cleared when read by CPU.  
A DAT3 edge has not been detected.  
A DAT3 edge has been detected.  
0
1
Data receive ready. DRRDY is cleared to 0 when the DAT logic is reset (DATRST = 1 in MMCCTL),  
when a command is sent with data receive/transmit clear (DCLR = 1 in MMCCMD), or when data is  
read from the MMC data receive register (MMCDRR).  
0
1
MMCDRR is not ready.  
MMCDRR is ready. New data has arrived and can be read by the CPU or by the DMA controller.  
9
DXRDY  
Data transmit ready. DXRDY is set to 1 when the DAT logic is reset (DATRST = 1 in MMCCTL), when a  
command is sent with data receive/transmit clear (DCLR = 1 in MMCCMD), or when data is written to  
the MMC data transmit register (MMCDXR).  
0
1
MMCDXR is not ready.  
MMCDXR is ready. The data in MMCDXR has been transmitted; MMCDXR can accept new data from  
the CPU or from the DMA controller.  
8
7
Reserved  
CRCRS  
0
Reserved  
Response CRC error.  
0
1
A response CRC error has not been detected.  
A response CRC error has been detected.  
Read-data CRC error.  
6
CRCRD  
0
1
A read-data CRC error has not been detected.  
A read-data CRC error has been detected.  
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Table 8. MMC Status Register 0 (MMCST0) Field Descriptions (continued)  
Bit  
Field  
Value Description  
5
CRCWR  
Write-data CRC error.  
0
1
A write-data CRC error has not been detected.  
A write-data CRC error has been detected.  
Response time-out event.  
4
3
2
1
0
TOUTRS  
TOUTRD  
RSPDNE  
BSYDNE  
DATDNE  
0
1
A response time-out event has not occurred.  
A time-out event has occurred while the MMC controller was waiting for a response to a command.  
Read-data time-out event.  
0
1
A read-data time-out event has not occurred.  
A time-out event has occurred while the MMC controller was waiting for data.  
Command/response done.  
0
1
No receiving response is done.  
Response successfully has received or command has sent without response.  
Busy done.  
0
1
No busy releasing is done.  
Released from busy state or expected busy is not detected.  
Data done  
0
1
The data has not been fully transmitted.  
The data has been fully transmitted.  
Note: 1) As the command portion and the data portion of the MMC/SD controller are  
independent, any command such as CMD0 (GO_IDLE_STATE) or CMD12  
(STOP_TRANSMISSION) can be sent to the card, even during block transfer. In this  
situation, the data portion detects this and waits, releasing the busy state only when the  
command sent was R1b (to be specific, command with BSYEXP bit), otherwise it  
continues transferring data.  
2) Bit 12 (TRNDNE) indicates that the last byte of a transfer has been completed. Bit 0  
(DATDNE) occurs at end of a transfer, but not until the CRC check and programming has  
completed.  
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4.4 MMC Status Register 1 (MMCST1)  
The MMC status register 1 (MMCST1) records specific events or errors. There are no interrupts  
associated with these events or errors.  
The MMC status register 1 (MMCST1) is shown in Figure 21 and described in Table 9.  
Figure 21. MMC Status Register 1 (MMCST1)  
31  
16  
8
Reserved  
R-0  
15  
Reserved  
R-0  
7
6
5
4
3
2
1
0
Reserved  
R-0  
FIFOFUL  
R-0  
FIFOEMP  
R-0  
DAT3ST  
R-0  
DRFUL  
R-0  
DXEMP  
R-0  
CLKSTP  
R-1  
BUSY  
R-0  
LEGEND: R = Read only; -n = value after reset  
Table 9. MMC Status Register 1 (MMCST1) Field Descriptions  
Bit  
31-7  
6
Field  
Value Description  
Reserved  
FIFOFUL  
0
Reserved  
FIFO is full.  
0
1
FIFO is not full.  
FIFO is full.  
5
4
3
FIFOEMP  
DAT3ST  
DRFUL  
FIFO is empty.  
0
1
FIFO is not empty.  
FIFO is empty.  
DAT3 status.  
0
1
The signal level on the DAT3 pin is a logic-low level.  
The signal level on the DAT3 pin is a logic-high level.  
Data receive register (MMCDRR) is full.  
0
1
A data receive register full condition is not detected. The data receive shift register is not full.  
A data receive register full condition is detected. The data receive shift register is full. No new bits can  
be shifted in from the memory card.  
2
1
0
DXEMP  
CLKSTP  
BUSY  
Data transmit register (MMCDXR) is empty.  
0
1
A data transmit register empty condition is not detected. The data transmit shift register is not empty.  
A data transmit register empty condition is detected. The data transmit shift register is empty. No bits  
are available to be shifted out to the memory card.  
Clock stop status.  
0
1
CLK is active. The memory clock signal is being driven on the pin.  
CLK is held low because of a manual stop (CLKEN = 0 in MMCCLK), receive shift register is full, or  
transmit shift register is empty.  
Busy.  
0
1
No busy signal is detected.  
A busy signal is detected (the memory card is busy).  
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4.5 MMC Interrupt Mask Register (MMCIM)  
The MMC interrupt mask register (MMCIM) is used to enable (bit = 1) or disable (bit = 0) status interrupts.  
If an interrupt is enabled, the transition from 0 to 1 of the corresponding interrupt bit in the MMC status  
register 0 (MMCST0) can cause an interrupt signal to be sent to the CPU.  
The MMC interrupt mask register (MMCIM) is shown in Figure 22 and described in Table 10.  
Figure 22. MMC Interrupt Mask Register (MMCIM)  
31  
16  
Reserved  
R-0  
15  
7
13  
12  
11  
10  
9
8
Reserved  
R-0  
ETRNDNE  
R/W-0  
EDATED  
R/W-0  
EDRRDY  
R/W-0  
EDXRDY  
R/W-0  
Reserved  
R-0  
6
5
4
3
2
1
0
ECRCRS  
R/W-0  
ECRCRD  
R/W-0  
ECRCWR  
R/W-0  
ETOUTRS  
R/W-0  
ETOUTRD  
R/W-0  
ERSPDNE  
R/W-0  
EBSYDNE  
R/W-0  
EDATDNE  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 10. MMC Interrupt Mask Register (MMCIM) Field Descriptions  
Bit  
Field  
Value Description  
31-13 Reserved  
0
Reserved  
12  
11  
10  
9
ETRNDNE  
EDATED  
EDRRDY  
EDXRDY  
Transfer done (TRNDNE) interrupt enable.  
Transfer done interrupt is disabled.  
0
1
Transfer done interrupt is enabled.  
DAT3 edge detect (DATED) interrupt enable.  
DAT3 edge detect interrupt is disabled.  
DAT3 edge detect interrupt is enabled.  
Data receive register ready (DRRDY) interrupt enable.  
Data receive register ready interrupt is disabled.  
Data receive register ready interrupt is enabled.  
Data transmit register (MMCDXR) ready interrupt enable.  
Data transmit register ready interrupt is disabled.  
Data transmit register ready interrupt is enabled.  
Reserved  
0
1
0
1
0
1
0
8
7
Reserved  
ECRCRS  
Response CRC error (CRCRS) interrupt enable.  
Response CRC error interrupt is disabled.  
Response CRC error interrupt is enabled.  
Read-data CRC error (CRCRD) interrupt enable.  
Read-data CRC error interrupt is disabled.  
Read-data CRC error interrupt is enabled.  
Write-data CRC error (CRCWR) interrupt enable.  
Write-data CRC error interrupt is disabled.  
Write-data CRC error interrupt is disabled.  
Response time-out event (TOUTRS) interrupt enable.  
Response time-out event interrupt is disabled.  
Response time-out event interrupt is enabled.  
0
1
6
5
4
ECRCRD  
ECRCWR  
ETOUTRS  
0
1
0
1
0
1
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Table 10. MMC Interrupt Mask Register (MMCIM) Field Descriptions (continued)  
Bit  
Field  
Value Description  
3
2
1
0
ETOUTRD  
ERSPDNE  
EBSYDNE  
EDATDNE  
Read-data time-out event (TOUTRD) interrupt enable.  
Read-data time-out event interrupt is disabled.  
Read-data time-out event interrupt is enabled.  
Command/response done (RSPDNE) interrupt enable.  
Command/response done interrupt is disabled.  
Command/response done interrupt is enabled.  
Busy done (BSYDNE) interrupt enable.  
Busy done interrupt is disabled.  
0
1
0
1
0
1
Busy done interrupt is enabled.  
Data done (DATDNE) interrupt enable.  
Data done interrupt is disabled.  
0
1
Data done interrupt is enabled.  
4.6 MMC Response Time-Out Register (MMCTOR)  
The MMC response time-out register (MMCTOR) defines how long the MMC controller waits for a  
response from a memory card before recording a time-out condition in the TOUTRS bit of the MMC status  
register 0 (MMCST0). If the corresponding ETOUTRS bit in the MMC interrupt mask register (MMCIM) is  
set, an interrupt is generated when the TOUTRS bit is set in MMCST0. If a memory card should require a  
longer time-out period than MMCTOR can provide, a software time-out mechanism can be implemented.  
The MMC response time-out register (MMCTOR) is shown in Figure 23 and described in Table 11.  
Figure 23. MMC Response Time-Out Register (MMCTOR)  
31  
15  
16  
Reserved  
R-0  
13  
12  
8
7
0
Reserved  
R-0  
TOD_20_16  
R/W-0  
TOR  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 11. MMC Response Time-Out Register (MMCTOR) Field Descriptions  
Bit  
Field  
Value Description  
31-13 Reserved  
0
Reserved  
12-8  
7-0  
TOD_20_16  
TOR  
0-1Fh Data read time-out count upper 5 bits. Used in conjunction with the TOD_15_0 bits in MMCTOD to  
form a 21-bit count. See MMCTOD (Section 4.7).  
0-FFh Time-out count for response.  
0
No time out  
1-FFh 1 CLK clock cycle to 255 CLK clock cycles  
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4.7 MMC Data Read Time-Out Register (MMCTOD)  
The MMC data read time-out register (MMCTOD) defines how long the MMC controller waits for the data  
from a memory card before recording a time-out condition in the TOUTRD bit of the MMC status register 0  
(MMCST0). If the corresponding ETOUTRD bit in the MMC interrupt mask register (MMCIM) is set, an  
interrupt is generated when the TOUTRD bit is set in MMCST0. If a memory card should require a longer  
time-out period than MMCTOD can provide, a software time-out mechanism can be implemented.  
The MMC data read time-out register (MMCTOD) is shown in Figure 24 and described in Table 12.  
Figure 24. MMC Data Read Time-Out Register (MMCTOD)  
31  
15  
16  
Reserved  
R-0  
0
TOD_15_0  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 12. MMC Data Read Time-Out Register (MMCTOD) Field Descriptions  
Bit  
31-16 Reserved  
15-0 TOD_15_0  
Field  
Value  
Description  
Reserved  
0
0-1F FFFFh Data read time-out count. Used in conjunction with the TOD_20_16 bits in MMCTOR to form a  
21-bit count. See MMCTOR (Section 4.6).  
0
No time out  
1-FFFFh  
1 CLK clock cycle to 2 097 151 CLK clock cycles  
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4.8 MMC Block Length Register (MMCBLEN)  
The MMC block length register (MMCBLEN) specifies the data block length in bytes. This value must  
match the block length setting in the memory card.  
The MMC block length register (MMCBLEN) is shown in Figure 25 and described in Table 13.  
Figure 25. MMC Block Length Register (MMCBLEN)  
31  
15  
16  
0
Reserved  
R-0  
12  
11  
Reserved  
R-0  
BLEN  
R/W-200h  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 13. MMC Block Length Register (MMCBLEN) Field Descriptions  
Bit  
Field  
Value  
0
Description  
31-12 Reserved  
11–0 BLEN  
Reserved  
1h–FFFh  
Block length. This field is used to set the block length, which is the byte count of a data block. The  
value 0 is prohibited.  
Note: The BLEN bits value must be the same as the CSD register settings in the MMC/SD card.  
To be precise, it should match the value of the READ_BL_LEN field for read, or  
WRITE_BL_LEN field for write.  
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4.9 MMC Number of Blocks Register (MMCNBLK)  
The MMC number of blocks register (MMCNBLK) specifies the number of blocks for a multiple-block  
transfer.  
The MMC number of blocks register (MMCNBLK) is shown in Figure 26 and described in Table 14.  
Figure 26. MMC Number of Blocks Register (MMCNBLK)  
31  
15  
16  
0
Reserved  
R-0  
NBLK  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 14. MMC Number of Blocks Register (MMCNBLK) Field Descriptions  
Bit  
31-16 Reserved  
15-0 NBLK  
Field  
Value  
Description  
Reserved  
0
0-FFFFh  
0
Number of blocks. This field is used to set the total number of blocks to be transferred.  
Infinite number of blocks. The MMC controller reads/writes blocks of data until a  
STOP_TRANSMISSION command is written to the MMC command register (MMCCMD).  
1h–FFFFh  
n blocks. The MMC controller reads/writes only n blocks of data, even if the  
STOP_TRANSMISSION command has not been written to the MMC command register  
(MMCCMD).  
4.10 MMC Number of Blocks Counter Register (MMCNBLC)  
The MMC number of blocks counter register (MMCNBLC) is a down-counter for tracking the number of  
blocks remaining to be transferred during a multiple-block transfer.  
The MMC number of blocks counter register (MMCNBLC) is shown in Figure 27 and described in  
Table 15.  
Figure 27. MMC Number of Blocks Counter Register (MMCNBLC)  
31  
15  
16  
Reserved  
R-0  
0
NBLC  
R-FFFFh  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 15. MMC Number of Blocks Counter Register (MMCNBLC) Field Descriptions  
Bit  
31-16 Reserved  
15-0 NBLC  
Field  
Value  
Description  
Reserved  
Read this field to determine the number of blocks remaining to be transferred.  
0
0–FFFFh  
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4.11 MMC Data Receive Register (MMCDRR)  
The MMC data receive register (MMCDRR) is used for storing the received data from the MMC controller.  
The CPU or the DMA controller can read data from this register. MMCDRR expects the data in  
little-endian format.  
The MMC data receive register (MMCDRR) is shown in Figure 28 and described in Table 16.  
Figure 28. MMC Data Receive Register (MMCDRR)  
31  
0
DRR  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
Table 16. MMC Data Receive Register (MMCDRR) Field Descriptions  
Bit  
Field  
Value  
Description  
31-0  
DRR  
0-FFFF FFFFh Data receive.  
4.12 MMC Data Transmit Register (MMCDXR)  
The MMC data transmit register (MMCDXR) is used for storing the data to be transmitted from the MMC  
controller to the memory card. The CPU or the DMA controller can write data to this register to be  
transmitted. MMCDXR expects the data in little-endian format.  
The MMC data transmit register (MMCDXR) is shown in Figure 29 and described in Table 17.  
Figure 29. MMC Data Transmit Register (MMCDXR)  
31  
0
DXR  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
Table 17. MMC Data Transmit Register (MMCDXR) Field Descriptions  
Bit  
Field  
Value  
Description  
31-0  
DXR  
0-FFFF FFFFh Data transmit.  
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4.13 MMC Command Register (MMCCMD)  
Note: Writing to the MMC command register (MMCCMD) causes the MMC controller to send the  
programmed command. Therefore, the MMC argument register (MMCARGHL) must be  
loaded properly before a write to MMCCMD.  
The MMC command register (MMCCMD) specifies the type of command to be sent and defines the  
operation (command, response, additional activity) for the MMC controller. The content of MMCCMD is  
kept after the transfer to the transmit shift register.  
When the ARM writes to MMCCMD, the MMC controller sends the programmed command, including any  
arguments in the MMC argument register (MMCARGHL). For the format of a command (index, arguments,  
and other bits), see Figure 31 and Table 19.  
The MMC command register (MMCCMD) is shown in Figure 30 and described in Table 18.  
Figure 30. MMC Command Register (MMCCMD)  
31  
24  
Reserved  
R-0  
23  
17  
9
16  
Reserved  
DMATRIG  
R/W-0  
R-0  
15  
14  
13  
12  
11  
10  
8
DCLR  
R/W-0  
INITCK  
R/W-0  
WDATX  
R/W-0  
STRMTP  
R/W-0  
DTRW  
R/W-0  
RSPFMT  
R/W-0  
BSYEXP  
R/W-0  
7
6
5
0
PPLEN  
R/W-0  
Reserved  
R-0  
CMD  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 18. MMC Command Register (MMCCMD) Field Descriptions  
Bit  
Field  
Value Description  
31-17 Reserved  
0
Reserved  
16  
15  
DMATRIG  
DCLR  
DMA transfer event generation enable.  
DMA transfer event generation is disabled.  
DMA transfer event generation is enabled.  
0
1
Data receive/transmit clear. Use this bit to clear the data receive ready (DRRDY) bit and the data  
transmit ready (DXRDY) bit in the MMC status register 0 (MMCST0) before a new read or write  
sequence. This clears any previous status.  
0
1
Do not clear DRRDY and DXRDY bits in MMCST0.  
Clear DRRDY and DXRDY bits in MMCST0.  
Initialization clock cycles.  
14  
13  
INITCK  
0
1
Do not insert initialization clock cycles.  
Insert initialization clock cycles; insert 80 CLK cycles before sending the command specified in the CMD  
bits. These dummy clock cycles are required for resetting a card after power on.  
WDATX  
Data transfer indicator.  
0
1
There is no data transfer.  
There is a data transfer associated with the command.  
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Table 18. MMC Command Register (MMCCMD) Field Descriptions (continued)  
Bit  
Field  
Value Description  
12  
STRMTP  
Stream enable.  
0
1
If WDATX = 1, the data transfer is a block transfer. The data transfer stops after the movement of the  
programmed number of bytes (defined by the programmed block size and the programmed number of  
blocks).  
If WDATX = 1, the data transfer is a stream transfer. Once the data transfer is started, the data transfer  
does not stop until the MMC controller issues a stop command to the memory card.  
11  
DTRW  
Write enable.  
0
1
If WDATX = 1, the data transfer is a read operation.  
If WDATX = 1, the data transfer is a write operation.  
Response format (expected type of response to the command).  
No response.  
10-9  
RSPFMT  
0-3h  
0
1h  
2h  
3h  
R1, R4, R5, or R6 response. 48 bits with CRC.  
R2 response. 136 bits with CRC.  
R3 response. 48 bits with no CRC.  
8
7
BSYEXP  
PPLEN  
Busy expected. If an R1b (R1 with busy) response is expected, set RSPFMT = 1h and BSYEXP = 1.  
A busy signal is not expected.  
0
1
A busy signal is expected.  
Push pull enable.  
0
1
0
Push pull driver of CMD line is disabled (open drain).  
Push pull driver of CMD line is enabled.  
Reserved.  
6
Reserved  
CMD  
5-0  
0-3Fh Command index. This field contains the command index for the command to be sent to the memory  
card.  
Figure 31. Command Format  
47  
46  
45  
40 39  
24  
Start Transmission  
23  
Command index  
Argument, high part  
8
7
1
0
Argument, low part  
CRC7  
End  
Table 19. Command Format  
Bit Position of  
Command  
Register  
Description  
47  
-
Start bit  
46  
-
Transmission bit  
Command index (CMD)  
Argument, high part (ARGH)  
Argument, low part (ARGL)  
CRC7  
45-40  
39-24  
23-8  
7-1  
MMCCMD(5-0)  
MMCARGHL  
MMCARGHL  
-
-
0
End bit  
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Registers  
4.14 MMC Argument Register (MMCARGHL)  
Note: Do not modify the MMC argument register (MMCARGHL) while it is being used for an  
operation.  
The MMC argument register (MMCARGHL) specifies the arguments to be sent with the command  
specified in the MMC command register (MMCCMD). Writing to MMCCMD causes the MMC controller to  
send a command; therefore, MMCARGHL must be configured before writing to MMCCMD. The content of  
MMCARGHL is kept after the transfer to the shift register; however, modification to MMCARGHL is not  
allowed during a sending operation. For the format of a command, see Figure 31 and Table 19.  
The MMC argument register (MMCARGHL) is shown in Figure 32 and described in Table 20.  
Figure 32. MMC Argument Register (MMCARGHL)  
31  
15  
16  
ARGH  
R/W-0  
0
ARGL  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
Table 20. MMC Argument Register (MMCARGHL) Field Descriptions  
Bit  
31-16 ARGH  
15-0 ARGL  
Field  
Value  
0-FFFFh  
0-FFFFh  
Description  
Argument, high part.  
Argument, low part.  
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4.15 MMC Response Registers (MMCRSP0-MMCRSP7)  
Each command has a preset response type. When the MMC controller receives a response, it is stored in  
some or all of the eight MMC response registers (MMCRSP7-MMCRSP0). The response registers are  
updated as the responses arrive, even if the CPU has not read the previous contents.  
As shown in Figure 33, Figure 34, Figure 35, and Figure 36 each of the MMC response registers holds up  
to 16 bits. Table 21 and Table 22 show the format for each type of response and which MMC response  
registers are used for the bits of the response. The first byte of the response is a command index byte and  
is stored in the MMC command index register (MMCCIDX).  
Figure 33. MMC Response Register 0 and 1 (MMCRSP01)  
31  
15  
16  
MMCRSP1  
R/W-0  
0
MMCRSP0  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
Figure 34. MMC Response Register 2 and 3 (MMCRSP23)  
31  
16  
0
MMCRSP3  
R/W-0  
15  
MMCRSP2  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
Figure 35. MMC Response Register 4 and 5 (MMCRSP45)  
31  
15  
16  
0
MMCRSP5  
R/W-0  
MMCRSP4  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
Figure 36. MMC Response Register 6 and 7 (MMCRSP67)  
31  
16  
0
MMCRSP7  
R/W-0  
15  
MMCRSP6  
R/W-0  
LEGEND: R/W = Read/Write; -n = value after reset  
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Registers  
Table 21. R1, R3, R4, R5, or R6 Response (48 Bits)  
Bit Position of Response  
Register  
47-40  
39-24  
23-8  
7-0  
MMCCIDX  
MMCRSP7  
MMCRSP6  
MMCRSP5(1)  
MMCRSP4-0  
-
(1) Bits 7-0 of the response are stored to bits 7-0 of MMCRSP5.  
Table 22. R2 Response (136 Bits)  
Bit Position of Response  
Register  
135-128  
127-112  
111-96  
95-80  
79-64  
63-48  
47-32  
31-16  
15-0  
MMCCIDX  
MMCRSP7  
MMCRSP6  
MMCRSP5  
MMCRSP4  
MMCRSP3  
MMCRSP2  
MMCRSP1  
MMCRSP0  
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4.16 MMC Data Response Register (MMCDRSP)  
After the MMC controller sends a data block to a memory card, the return byte from the memory card is  
stored in the MMC data response register (MMCDRSP).  
The MMC data response register (MMCDRSP) is shown in Figure 37 and described in Table 23.  
Figure 37. MMC Data Response Register (MMCDRSP)  
31  
15  
16  
Reserved  
R-0  
8
7
0
Reserved  
R-0  
DRSP  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 23. MMC Data Response Register (MMCDRSP) Field Descriptions  
Bit  
31-8  
7-0  
Field  
Value Description  
Reserved  
DRSP  
0
Reserved  
0-FFh During a write operation (see Section 2.3.1), the CRC status token is stored in DRSP.  
4.17 MMC Command Index Register (MMCCIDX)  
The MMC command index register (MMCCIDX) stores the first byte of a response from a memory card.  
Table 21 and Table 22 show the format for each type of response.  
The MMC command index register (MMCCIDX) is shown in Figure 38 and described in Table 24.  
Figure 38. MMC Command Index Register (MMCCIDX)  
31  
15  
16  
Reserved  
R-0  
8
7
6
5
0
Reserved  
R-0  
STRT XMIT  
R/W-0 R/W-0  
CIDX  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 24. MMC Command Index Register (MMCCIDX) Field Descriptions  
Bit  
31-8  
7
Field  
Value Description  
Reserved  
STRT  
XMIT  
0
Reserved  
0-1  
0-1  
Start bit. When the MMC controller receives a response, the start bit is stored in STRT.  
6
Transmission bit. When the MMC controller receives a response, the transmission bit is stored in XMIT.  
5-0  
CIDX  
0-3Fh Command index. When the MMC controller receives a response, the command index is stored in CIDX.  
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Registers  
4.18 MMC FIFO Control Register (MMCFIFOCTL)  
The MMC FIFO control register (MMCFIFOCTL) is shown in Figure 39 and described in Table 25.  
Figure 39. MMC FIFO Control Register (MMCFIFOCTL)  
31  
16  
Reserved  
R-0  
15  
5
4
3
2
1
0
Reserved  
R-0  
ACCWD  
R/W-0  
FIFOLEV  
R/W-0  
FIFODIR  
R/W-0  
FIFORST  
R/W-0  
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset  
Table 25. MMC FIFO Control Register (MMCFIFOCTL) Field Descriptions  
Bit  
31-5  
4-3  
Field  
Value Description  
Reserved  
ACCWD  
0
0-3h  
0
Reserved  
Access width. Used by FIFO control to determine full/empty flag.  
CPU/EDMA access width of 4 bytes  
CPU/EDMA access width of 3 bytes  
CPU/EDMA access width of 2 bytes  
CPU/EDMA access width of 1 byte  
1h  
2h  
3h  
2
FIFOLEV  
FIFO level. Sets the threshold level that determines when the EDMA request and the FIFO threshold  
interrupt are triggered.  
0
1
EDMA request every 128 bits sent/received.  
EDMA request every 256 bits sent/received.  
FIFO direction. Determines if the FIFO is being written to or read from.  
Read from FIFO.  
1
0
FIFODIR  
FIFORST  
0
1
Write to FIFO.  
FIFO reset. Resets the internal state of the FIFO.  
FIFO reset is disabled.  
0
1
FIFO reset is enabled.  
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Appendix A  
Appendix A Revision History  
Table A-1 lists the changes made since the previous version of this document.  
Table A-1. Document Revision History  
Reference  
Additions/Modifications/Deletions  
Section 1.2  
Changed third bullet.  
Added seventh bullet.  
Section 1.3  
Section 1.5  
Section 2  
Added second sentence.  
Deleted third bullet.  
Changed second sentence in second paragraph.  
Changed Figure 3.  
Figure 3  
Section 2.1  
Figure 4  
Changed first sentence in second paragraph.  
Changed Figure 4.  
Table 1  
Changed table headings.  
Section 2.3.1  
Section 2.3.2  
Section 2.4  
Changed Section 2.3.1.  
Changed Section 2.3.2.  
Added fourth sentence.  
Changed first bullet.  
Figure 7  
Changed Figure 7.  
Section 2.5  
Changed first sentence.  
Changed last sentence.  
Section 2.6.1  
Section 2.6.2  
Section 2.7.1  
Changed third sentence in second paragraph.  
Added second paragraph.  
Changed first sentence.  
Added last sentence.  
Changed second sentence in second paragraph.  
Added second paragraph.  
Section 2.7.2  
Section 2.9.1  
Section 2.9.2  
Section 2.9.7  
Section 2.10.1  
Section 3.1  
Added Note.  
Changed section title.  
Added Note after fourth bullet.  
Changed first sentence.  
Deleted second paragraph.  
Deleted subsection 2.9.7.1: Detecting Edges on the DAT3 Pin  
Deleted subsection 2.9.7.2: Detecting Level Changes on the DAT3 Pin  
Changed second paragraph.  
Added Note.  
Changed Section 3.1.  
Added Section 3.1.1.  
Added Section 3.1.2.  
Section 3.9  
Table 5  
Deleted section 3.10: SDIO Card Function  
Changed Table 5.  
Section 4  
Deleted section 4.18: SDIO Control Register (SDIOCTL)  
Deleted section 4.19: SDIO Status Register 0 (SDIOST0)  
Deleted section 4.20: SDIO Interrupt Enable Register (SDIOIEN)  
Deleted section 4.21: SDIO Interrupt Status Register (SDIOIST)  
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60  
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