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Preliminary
S3C2451X RISC MICROPROCESSOR
HSMMC CONTROLLER
21-37
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
BLOCK GAP CONTROL REGISTER
This register contains the SD Command Argument.
Register Address
R/W
Description
Reset
Value
BLKGAP0
0X4AC0002A
R/W
Block Gap Control Register (Channel
0)
0x0
BLKGAP1
0X4A80002A
R/W
Block Gap Control Register (Channel
1)
0x0
Name Bit
Description
Initial
Value
[7:4]
Reserved
0
ENINT
BGAP
[3]
Interrupt At Block Gap
This bit is valid only in 4-bit mode of the SDIO card and selects a sample point in the
interrupt cycle. Setting to 1 enables interrupt detection at the block gap for a multiple
block transfer. Setting to 0 disables interrupt detection during a multiple block transfer.
If the SD card cannot signal an interrupt during a multiple block transfer, this bit
should be set to 0. When the Host Driver detects an SD card insertion, it shall set this
bit according to the CCCR of the SDIO card. (RW)
‘1’ = Enabled
‘0’ = Disabled
0
ENRW
AIT
[2]
Read Wait Control
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 the
DAT
[2] line.
Otherwise the Host Controller has to stop the SD Clock to hold read data, which
restricts commands generation. When the Host Driver 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. (RW)
‘1’ = Enable Read Wait Control
‘0’ = Disable Read Wait Control
0
CONT
REQ
[1]
Continue Request
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 1 to restart the transfer.
The Host Controller 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. (RWAC)
‘1’ = Restart
‘0’ = Not affect
0
STOP
BGAP
[0]
Stop At Block Gap Request
This bit is used to stop executing a transaction at the next block gap for both DMA and
non-DMA transfers. Until the
Transfer Complete
is set to 1, indicating a transfer
completion the Host Driver shall leave this bit set to 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
0