RM0082
RS_SDIO controller
Doc ID 018672 Rev 1
709/844
[02]
RDWCTRL
1’h0
RW
The read wait function is optional for SDIO cards. If the
card supports read wait, set this bit to enable use of the
read wait protocol to stop read data using DAT[2] line.
Otherwise the HC has to stop the SD clock to hold read
data, which restricts commands generation. When the
HD detects an SD card insertion, it shall set this bit
according to the CCCR of the SDIO card. If the card
does not support read wait, this bit shall never be set to
logic ‘1’ otherwise DAT line conflict may occur. If this bit
is set to logic ‘0’, Suspend / Resume cannot be
supported
1’b1 - Enable Read Wait Control
1’b0 - Disable Read Wait Control
[01]
CNTREQ
1’h0
RW
This bit is used to restart a transaction which was
stopped using the Stop At Block Gap Request. To cancel
stop at the block gap, set Stop At block Gap Request to
logic ‘0’ and set this bit to restart the transfer. The HC
automatically clears this bit in either of the following
cases:
In the case of a read transaction, the DAT Line Active
changes from 0 to 1 as a read transaction restarts.
In the case of a write transaction, the Write transfer
active changes from 0 to 1 as the write transaction
restarts.
Therefore it is not necessary for Host driver to set this bit
to logic ‘0’. If Stop At Block Gap Request is set to logic
‘1’, any write to this bit is ignored.
1’b1 - Restart
1’b0 - Ignored
Table 631.
BLKGAPCTRL register bit assignments (continued)
Bit
Name
Reset
value
Type
Description