Texas Instruments TMS320DM644x specification

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Peripheral Architecture

2.5Data 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

1st

2nd

3rd

4th

MMCDRR or MMCDXR registers

3			0
4th	3rd	2nd	1st

Support byten = ”1111”

1st

2nd

3rd

1st

2nd

3			0
	3rd	2nd	1st

Support byten = ”0111”

3			0
		2nd	1st

Support byten = ”0011”

3

1st

0

1st

Support byten = ”0001”

SPRUE30B –September 2006

Multimedia Card (MMC)/Secure Digital (SD) Card Controller

17

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Texas Instruments TMS320DM644x manual Data Flow in the Data Registers Mmcdrr and Mmcdxr

Contents

Users Guide Submit Documentation Feedback Contents Appendix a List of Figures List of Tables Read This First Trademarks Purpose of the Peripheral FeaturesFunctional Block Diagram Industry Standards Compliance Statement Supported Use Case Statement MMC/SD Controller Interface Diagram Clock Control MMC/SD Controller Clocking Diagram MMC/SD Controller Pins Used in Each Mode Signal Descriptions1 MMC/SD Mode Write Sequence Protocol Descriptions Portion Sequence Description MMC/SD Mode Write Sequence2 MMC/SD Mode Read Sequence Data Flow in the Input/Output Fifo MMC/SD Mode Read SequenceCRC RD CMD Fifo Operation Diagram 1st 2nd 3rd 4th Mmcdrr or Mmcdxr registers Support byten = Data Flow in the Data Registers Mmcdrr and Mmcdxr 1st 2nd 3rd 4th Support byten = 1111 1110 CPU Reads Fifo Operation During Card Read OperationEdma Reads Fifo Operation During Card Read Diagram CPU Writes Fifo Operation During Card Write OperationEdma Writes Fifo Operation During Card Write Diagram Initialization Reset Considerations Initialize the Interrupt Mask Register Mmcim Initializing the Clock Controller Registers MmcclkInitialize the Time-Out Registers Mmctor and Mmctod Initialize the Data Block Registers Mmcblen and Mmcnblk Determining Whether New Data is Available in Mmcdrr Monitoring Activity in the MMC/SD Mode Checking For a Data Transmit Empty Condition Interrupt Events and Requests Interrupt SupportInterrupt Multiplexing Description of MMC/SD Interrupt Requests Emulation Considerations Power ManagementDMA Event Support Card Identification Operation MMC Card Identification Procedure Procedures for Common Operations SD Card Identification Procedure MMC/SD Mode Single-Block Write Operation Using CPU MMC/SD Mode Single-Block Write Operation MMC/SD Mode Single-Block Read Operation Using the CPU MMC/SD Mode Single-Block Write Operation Using the Edma MMC/SD Mode Single-Block Read Operation MMC/SD Mode Single-Block Read Operation Using Edma MMC/SD Mode Multiple-Block Write Operation Using CPU MMC/SD Multiple-Block Write Operation MMC/SD Mode Multiple-Block Read Operation Using CPU MMC/SD Mode Multiple-Block Write Operation Using Edma MMC/SD Mode Multiple-Block Read Operation MMC/SD Mode Multiple-Block Read Operation Using Edma Offset Acronym Register Description Bit Field Value Description MMC Control Register MmcctlMMC Control Register Mmcctl Field Descriptions MMC Memory Clock Control Register Mmcclk Field Descriptions MMC Memory Clock Control Register MmcclkClken Clkrt Clken Bit Field MMC Status Register 0 MMCST0MMC Status Register 0 MMCST0 Field Descriptions Write-data CRC error MMC Status Register 1 MMCST1 Field Descriptions MMC Status Register 1 MMCST1Fifoful Fifoemp DAT3ST Drful Dxemp Clkstp Busy Fifoful MMC Interrupt Mask Register Mmcim Field Descriptions MMC Interrupt Mask Register MmcimEtrndne Edated Edrrdy Edxrdy Etrndne TOR MMC Response Time-Out Register MmctorMMC Response Time-Out Register Mmctor Field Descriptions MMC Data Read Time-Out Register Mmctod Field Descriptions MMC Data Read Time-Out Register Mmctod Blen MMC Block Length Register MmcblenMMC Block Length Register Mmcblen Field Descriptions MMC Number of Blocks Counter Register Mmcnblc MMC Number of Blocks Register MmcnblkMMC Number of Blocks Register Mmcnblk Field Descriptions Nblk MMC Data Transmit Register Mmcdxr MMC Data Receive Register MmcdrrMMC Data Receive Register Mmcdrr Field Descriptions MMC Data Transmit Register Mmcdxr Field Descriptions MMC Command Register Mmccmd Field Descriptions MMC Command Register MmccmdDmatrig Dclr Initck Wdatx Strmtp Dtrw Rspfmt Bsyexp Pplen CRC7 Stream enableBit Position Command Register Description MMC Argument Register Mmcarghl Field Descriptions MMC Argument Register MmcarghlArgh Argl MMC Response Registers MMCRSP0-MMCRSP7 R2 Response 136 Bits R1, R3, R4, R5, or R6 Response 48 BitsBit Position of Response Register MMCRSP4-0 MMC Command Index Register Mmccidx Field Descriptions MMC Command Index Register MmccidxMMC Data Response Register Mmcdrsp MMC Data Response Register Mmcdrsp Field Descriptions MMC Fifo Control Register Mmcfifoctl Field Descriptions MMC Fifo Control Register MmcfifoctlAccwd Fifolev Fifodir Fiforst Accwd Reference Additions/Modifications/Deletions Table A-1. Document Revision History Appendix a Important Notice