S1R72105 Technical Manual
34
EPSON
Rev.1.0
7.3.33 SCSI Control (SCSICTL) R/W
This register is accessed when the CPU directly controls SCSI signal lines.
For such direct control, DIRECT (bit 1) must be set in the mode setting register (0Ah).
The status of each signal is stored as “active high”.
Address
Register Name
Bit Symbol
Description
2Bh
SCSICTL
7: ACK
SCSI ACK
6: ATN
SCSI ATN
5: SEL
SCSI SEL
4: BSY
SCSI BSY
3: REQ
SCSI REQ
2: MSG
SCSI MSG
1: I/O
SCSI I/O
0: C/D
SCSI C/D
7.3.34 SCSI Data (SCSIDATA) R/W
This register is accessed when the CPU directly controls the SCSI data bus. For such direct control, DIRECT
(bit 1) must be set in the mode setting register (0Ah).
The status of each signal is stored as “active high”. The DIRECT setting does not determine whether the
parity bit is output or not. It is output if it has been output before setting DIRECT, or it is not otherwise.
Address
Register Name
Bit Symbol
Description
2Ch SCSIDATA
7:
DB7
6:
DB6
5:
DB5
4:
DB4
SCSIDATA
3:
DB3
2:
DB2
1:
DB1
0:
DB0