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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 1553
UG585 (v1.11) September 27, 2016
Appendix B: Register Details
Read_Wait_Control 18 rw 0x0 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 1 otherwise DAT line conflict may
occur. If this bit is set to 0, Suspend / Resume
cannot be supported
1 - Enable Read Wait Control
0 - Disable Read Wait Control
Continue_Request 17 rw 0x0 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 0 and set this bit to restart the
transfer.
The HC automatically clears this bit in either of
the following cases:
1) In the case of a read transaction, the DAT Line
Active changes from 0 to 1 as a read transaction
restarts.
2) 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 0. If Stop At Block Gap Request is set to
1, any write to this bit is ignored.
1 - Restart
0 - Ignored
Field Name Bits Type Reset Value Description