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SD-HOST Registers
381
SWRU543–January 2019
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SD Host Controller Interface
11.7.5 MMCHS_CMD Register (Offset = 20Ch) [reset = 0h]
Command and Transfer Mode register
MMCHS_CMD is shown in Figure 11-6 and described in Table 11-9.
Return to Summary Table.
MMCi.MMCHS_CMD[31:16] = the command register
MMCi.MMCHS_CMD[15:0] = the transfer mode.
This register configures the data and command transfers. A write into the most significant byte sends the
command. A write into MMCi.MMCHS_CMD[15:0] registers during data transfer has no effect. This
register shall be used for any card.
Figure 11-6. MMCHS_CMD Register
31 30 29 28 27 26 25 24
RESERVED INDX
R-0h R/W-0h
23 22 21 20 19 18 17 16
CMD_TYPE DP CICE CCCE RESERVED RSP_TYPE
R/W-0h R/W-0h R/W-0h R/W-0h R-0h R/W-0h
15 14 13 12 11 10 9 8
RESERVED
R-0h
7 6 5 4 3 2 1 0
RESERVED MSBS DDIR RESERVED BCE DE
R-0h R/W-0h R/W-0h R-0h R/W-0h R/W-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 11-9. MMCHS_CMD Register Field Descriptions
Bit Field Type Reset Description
31-30 RESERVED R 0h
29-24 INDX R/W 0h
Command index
Binary-encoded value from 0 to 63, specifying the command number
send to card.
0h = CMD0 or ACMD0
1h = CMD1 or ACMD1 3Fh = CMD63 or ACMD63
23-22 CMD_TYPE R/W 0h
Command type
This register specifies three types of special commands: Suspend,
Resume, and Abort. These bits shall be set to 0b00 for all other
commands.
0h = Other commands
1h = Upon CMD52 Bus Suspend operation
2h = Upon CMD52 Function Select operation
3h = Upon CMD12 or CMD52 I/O Abort command
21 DP R/W 0h
Data present select
This register indicates that data is present, and mmci_dat line shall
be used. It must be set to 0 in the following conditions: Command
using only mmci_cmd line Command with no data transfer, but using
busy signal on mmci_dat[0] Resume command
0h = Command with no data transfer
1h = Command with data transfer
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