RM0082
RS_SDIO controller
Doc ID 018672 Rev 1
701/844
32.7.6 CMD
register
The CMD bit assignments are given in
.
Table 623.
CMD register bit assignments
Bit
Name
Reset
value
Type
Description
[15:14]
-
-
Rsvd
Reserved
[13:08]
CMDIndex
6’h0
RW
This bit shall be set to the command number
(CMD0-63, ACMD0- 63).
[07:06]
CMDType
2’h0
RW
There are three types of special commands.
Suspend, Resume and Abort. These bits shall be
set to 2’b00 for all other commands.
Suspend Command
If the Suspend command succeeds, the HC shall
assume the SD Bus has been released and that it
is possible to issue the next command which uses
the DAT line. The HC shall de-assert Read Wait for
read transactions and stop checking busy for write
transactions. The Interrupt cycle shall start, in 4 bit
mode. If the Suspend command fails, the HC shall
maintain its current state. and the HD shall restart
the transfer by setting Continue Request in the
Block Gap Control Register.
Resume Command
The HD re-starts the data transfer by restoring the
registers in the range of 0x000-0x00D. The HC
shall check for busy before starting write transfers.
Abort Command
If this command is set when executing a read
transfer, the HC shall stop reads to the buffer. If this
command is set when executing a write transfer, the
HC shall stop driving the DAT line. After issuing the
Abort command, the HD should issue a software
reset
2’b00 - Normal
2’b01 - Suspend
2’b10 - Resume
2’b11 - Abort
[05]
DPSel
1’h0
RW
This bit is set to logic ‘1’ to indicate that data is
present and shall be transferred using the DAT line.
It is set to logic ‘0’ for the following:
Commands using only CMD line (ex. CMD52)
Commands with no data transfer but using busy
signal on DAT[0] line (R1b or R5b ex. CMD38)
Resume Command
1’b0 - No Data Present
1’b1 - Data Present