Samsung S3C2451X User Manual page 492

HSMMC CONTROLLER
COMMAND REGISTER
This register contains the SD Command Argument.
Register
CMDREG0
CMDREG1
The Host Driver shall check the Command Inhibit (DAT) bit and Command Inhibit (CMD) bit in the Present
State register before writing to this register. Writing to the upper byte of this register triggers SD command
generation. The Host Driver has the responsibility to write this register because the Host Controller does not
protect for writing when Command Inhibit (CMD) is set.
Name Bit
[15:14] Reserved
[13:8]
CMDIDX Command Index
These bits shall be set to the command number (CMD0-63, ACMD0-63) that is
specified in bits 45-40 of the Command-Format in the SD Memory Card Physical
Layer Specification and SDIO Card Specification.
[7:6]
CMDTYP
Command Type
There are three types of special commands: Suspend, Resume and Abort.
These bits shall be set to 00b for all other commands.
• Suspend Command
If the Suspend command succeeds, the Host Controller shall assume the SD
Bus has been released and that it is possible to issue the next command which
uses the DAT line. The Host Controller 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 Host Controller shall
maintain its current state, and the Host Driver shall restart the transfer by setting
Continue Request in the Block Gap Control register.
• Resume Command
The Host Driver re-starts the data transfer by restoring the registers in the range
of 000-00Dh. (Refer to Suspend and Resume mechanism) The Host Controller
shall check for busy before starting write transfers.
• Abort Command
If this command is set when executing a read transfer, the Host Controller shall
stop reads to the buffer. If this command is set when executing a write transfer,
the Host Controller shall stop driving the DAT line. After issuing the Abort
command, the Host Driver should issue a software reset. (Refer to Abort
Transaction)
11b = Abort CMD12, CMD52 for writing "I/O Abort" in CCCR
10b = Resume CMD52 for writing "Function Select" in CCCR
01b = Suspend CMD52 for writing "Bus Suspend" in CCCR
00b = Normal Other commands
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
21-24
Specifications and information herein are subject to change without notice.
Address
0X4AC0000E
0X4A80000E
R/W Description
R/W Command Register (Channel 0)
R/W Command Register (Channel 1)
Description
S3C2451X RISC MICROPROCESSOR
Reset Value
0x0
0x0
Initial
Value