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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 1545
UG585 (v1.11) September 27, 2016
Appendix B: Register Details
Command_Type 23:22 rw 0x0 There are three types of special commands.
Suspend, Resume and Abort. These bits shall bet
set to 00b 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 000-00Dh. 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
00b - Normal
01b - Suspend
10b - Resume
11b - Abort
Data_Present_Select 21 rw 0x0 This bit is set to 1 to indicate that data is present
and shall be transferred using the DAT line. If is
set to 0 for the following:
1. Commands using only CMD line (ex. CMD52)
2. Commands with no data transfer but using
busy signal on DAT[0]
line (R1b or R5b ex. CMD38)
3. Resume Command
0 - No Data Present
1 - Data Present
Command_Index_Che
ck_Enable
20 rw 0x0 If this bit is set to 1, the HC shall check the index
field in the response to see if it has the same value
as the command index. If it is not, it is reported as
a Command Index Error. If this bit is set to 0, the
Index field is not checked.
0 - Disable
1 - Enable
Field Name Bits Type Reset Value Description