LSI LSI53C896, Technical Manual

Page: 151 / 370

SCSI Registers 4-39
This register also contains the state of the lower eight bits of the SCSI
data bus during the Selection phase if the COM bit in the
DMA Control
(DCNTL) register is clear.
If the COM bit is cleared, do not access this register using SCRIPTS
operations, as nondeterminate operations may occur. (This includes
SCRIPTS Read/Write operations and conditional transfer control
instructions that initialize the
SCSI First Byte Received (SFBR) register.)
Register: 0x09
SCSI Output Control Latch (SOCL)
Read/Write
REQ Assert SCSI REQ/ Signal 7
ACK Assert SCSI ACK/ Signal 6
BSY Assert SCSI BSY/ Signal 5
SEL Assert SCSI SEL/ Signal 4
ATN Assert SCSI ATN/ Signal 3
MSG Assert SCSI MSG/ Signal 2
C_D Assert SCSI C_D/ Signal 1
I/O Assert SCSI I_O/ Signal 0
This register is used primarily for diagnostic testing or programmed I/O
operation. It is controlled by the SCRIPTS processor when executing
SCSI SCRIPTS.
SCSI Output Control Latch (SOCL) is used only when
transferring data using programmed I/O. Some bits are set or cleared
when executing SCSI SCRIPTS. Do not write to the register once the
LSI53C896 SCSI function starts executing normal SCSI SCRIPTS.
7 6 5 4 3 2 1 0
REQ ACK BSY SEL ATN MSG C_D I/O
0 0 0 0 0 0 0 0
*