Registers
1310
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multimedia Card (MMC)/Secure Digital (SD) Card Controller
Table 26-18. MMC Command Register (MMCCMD) Field Descriptions (continued)
Bit
Field
Value
Description
12
STRMTP
Stream enable.
0
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).
1
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
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 26-30. 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 26-19. 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