RM0321 Datasheet, PDF (242/584 Pages) STMicroelectronics – SPEAr320S address map and registers

MMC-SD card/SDIO controller
RM0321
Table 280. BLKGAPCTRL register bit assignments (continued)
Bit Name
Reset
value
Type Description
[00]
STPBKGPR
EQ
1’h0
This bit is used to stop executing a transaction at the
next block gap for non- DMA,SDMA and ADMA
transfers. Until the transfer complete is set to logic ‘1’,
indicating a transfer completion the HD shall leave this
bit set to logic ‘1’. Clearing both the Stop At Block Gap
Request and Continue Request shall not cause the
transaction to restart. Read Wait is used to stop the read
transaction at the block gap. The HC shall honour Stop
At Block Gap Request for write transfers, but for read
transfers it requires that the SD card support Read Wait.
Therefore the HD shall not set this bit during read
RW _{transfers unless the SD card supports Read Wait and}
has set Read Wait Control to logic ‘1’. In case of write
transfers in which the HD writes data to the Buffer Data
Port register, the HD shall set this bit after all block data
is written. If this bit is set to logic ‘1’, the HD shall not
write data to Buffer data port register. This bit affects
Read Transfer Active, Write Transfer Active, DAT line
active and Command Inhibit (DAT) in the Present State
register.
1’b1 - Stop
1’b0 - Transfer
There are three cases to restart the transfer after stop at the block gap. Which case is
appropriate depends on whether the HC issues a Suspend command or the SD card
accepts the Suspend command.
1. If the HD does not issue a Suspend command, the Continue Request shall be used to
restart the transfer.
2. If the HD issues a Suspend command and the SD card accepts it, a Resume
Command shall be used to restart the transfer.
3. If the HD issues a Suspend command and the SD card does not accept it, the Continue
Request shall be used to restart the transfer.
Any time Stop At Block Gap Request stops the data transfer, the HD shall wait for Transfer
Complete (in the Normal Interrupt Status register) before attempting to restart the transfer.
When restarting the data transfer by Continue Request, the HD shall clear Stop At Block
Gap Request before or simultaneously.
12.2.13 WKUPCTRL register
Table 281. WKUPCTRL register bit assignments
Bit Name
Reset
value
Type Description
[07:03] -
-
Rsvd Reserved
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