Texas Instruments TMS320DM644x Stream enable, CRC7, Bit Position Command Register Description

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Registers

Table 18. MMC Command Register (MMCCMD) Field Descriptions (continued)

Bit	Field	Value Description
12	STRMTP	Stream enable.

0If 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).

1If 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	If WDATX = 1, the data transfer is a read operation.
		1	If WDATX = 1, the data transfer is a write operation.
10-9	RSPFMT	0-3h	Response format (expected type of response to the command).
		0	No response.
		1h	R1, R4, R5, or R6 response. 48 bits with CRC.
		2h	R2 response. 136 bits with CRC.
		3h	R3 response. 48 bits with no CRC.
8	BSYEXP		Busy expected. If an R1b (R1 with busy) response is expected, set RSPFMT = 1h and BSYEXP = 1.
		0	A busy signal is not expected.
		1	A busy signal is expected.
7	PPLEN		Push pull enable.
		0	Push pull driver of CMD line is disabled (open drain).
		1	Push pull driver of CMD line is enabled.
6	Reserved	0	Reserved.
5-0	CMD	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		Command index		Argument, high part
23					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
45-40	MMCCMD(5-0)	Command index (CMD)
39-24	MMCARGHL	Argument, high part (ARGH)
23-8	MMCARGHL	Argument, low part (ARGL)
7-1	-	CRC7
0	-	End bit

SPRUE30B –September 2006	Multimedia Card (MMC)/Secure Digital (SD) Card Controller	53
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