S1R72105 Technical Manual
30
EPSON
Rev.1.0
7.3.29 SCSI Interrupt Status 1 (SCSIINT1) R/W
Shows the result of executing the SCSI control command.
The CPU identifies the source of interruption by reading this register after receiving the interrupt signal. It
clears the bit by writing the value read again.
Address
Register Name
Bit Symbol
Description
21h
SCSIINT1
7: SPERR
SCSI DATA PARITY ERROR DETECTED
6: IDERR
ID ERROR DETECTED
5: SELTO
SELECTION TIME OUT
4: SATN
SCSI ATN ASSERTION DETECTED
3: BFREE
BUS FREE DETECTED
2: ILPHS
ILLEGAL PHASE CHANGE DETECTED
1: SCSEL
SCAM SELECTED
0: WOATN
SELECTED WITHOUT ATTENTION
BIT7 SCSI DATA PARITY ERROR DETECTED
This bit becomes HIGH when a parity error is detected on the SCSI data bus.
BIT6 ID ERROR DETECTED
This bit becomes HIGH when an error related to the ID bit is detected during the selection or reselection phase. The
errors related to the ID bit are as described below:
Only one ID bit is asserted, or
Three or more ID bits are asserted.
BIT5 SELECTION TIME OUT
This bit becomes HIGH when time-out is detected during the selection or reselection phase.
BIT4 SCSI ATN ASSERTION DETECTED
This bit becomes HIGH when SCSI ATN is asserted. It is not set, however, in the regular sequence of assertion of
SCSI ATN. In other words, this bit is not set in the message-out phase immediately following selection.
BIT3 BUS FREE DETECTED
This bit becomes HIGH when the bus-free phase is detected during execution of the SCSI control command.
BIT2 ILLEGAL PHASE CHANGE DETECTED
This bit becomes HIGH when unexpected phase transition is detected during execution of the SCSI control command.
It is valid only in Initiator mode.
BIT1 SCAM SELECTED
This bit becomes HIGH when the SCAM selection is responded to.
BIT0 SELECTED WITHOUT ATTENTION
This bit becomes HIGH when the selection, which is not asserted ATTENTION, is responded to.
Execution of the SCSI control command continues, even when this bit is set. If a command block is received
continuously, however, the first byte of SCSI-FIFO has the command code.