Preliminary
HSMMC CONTROLLER
S3C2451X RISC MICROPROCESSOR
21-38
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. The Host Controller shall honor
Stop At Block Gap Request
for write
transfers, but for read transfers it requires that the SD card support Read Wait.
Therefore the Host Driver shall not set this bit during read transfers unless the SD
card supports Read Wait and has set
Read Wait Control
to 1. In the case of write
transfers in which the Host Driver writes data to the
Buffer Data Port
register, the Host
Driver shall set this bit after all block data is written. If this bit is set to 1, the Host
Driver 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. Regarding detailed control of
bits D01 and D00. (RW)
‘1’ = Stop
‘0’ = Transfer
There are three cases to restart the transfer after stop at the block gap. Which case is appropriate depends on
whether the Host Controller issues a Suspend command or the SD card accepts the Suspend command.
(1) If the Host Driver does not issue a Suspend command, the
Continue Request
shall be used to restart the
transfer.
(2) If the Host Driver issues a Suspend command and the SD card accepts it, a Resume command shall be used
to restart the transfer.
(3) If the Host Driver 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 Host Driver 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 Host Driver shall clear
Stop At Block Gap Request
before or simultaneously.
Note : After setting
Stop At Block Gap Request
field, which should not be cleared unless Block Gap Event or
Transfer Complete interrupt occurs. Otherwise, the module hangs.