Samsung S3C6400X User Manual page 209

CF CONTROLLER
ATA_COMMAND
Register
ATA_COMMAND 0x70301908
ATA_COMMAND
Reserved
XFR_COMMAND
The STOP command is used when CPU wants to pause data transfer. The CPU uses STOP command to judge
the transmission data is valid or not while transfer transmits.
To resume the data transfer use CONTINUE command.
The STOP command does control ATA Device side signal but does not control DMA side. Namely, if the FIFO
has data after STOP command, DMA operation progresses until the FIFO is empty at read operation. In case of
write operation, the DMA acts the same way until the FIFO is full.
The ABORT command is used when the transmitting data has proved useless data. Also, this command
discontinues absurd state by error interrupt from device.
At that time, all data in ATA Host controller (register, FIFO) cleared and the transmission state machine switches
to IDLE.
The Software Reset's meaning become clear all registers irrespective of the ABORT command being executed
before do configuration register set for next transmission. It is not mandatory.
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.
9-22
Address
Bits
[31:2] Reserved bits
[1:0] ATA transfer command
Four command types (START, STOP, ABORT and
CONTINUE) are supported for data transfer
control. The "START" command is used to start
data transfer. The "STOP" command can pause
transfer temporarily. The "CONTINUE" command
shall be used after "STOP" command or internal
state of "pause" when track buffer is full or UDMA
hold state. The "ABORT" command terminates
current data transfer sequences and make ATA
host controller move to idle state.
00 : command stop
01 : command start (Only available in idle state)
10 : command abort
11 : command continue (Only available in
transfer pause)
** After issuing the ABORT command, make
software reset by setting ATA_SWRST [0] to clear
the leftover values of internal registers.
S3C6400X RISC MICROPROCESSOR
Description
ATA command
Description
Reset Value
0x0000_0000
R/W Reset
Value
R 0x0
R/W 0x0