SCSI Functional Description 2-25
Table 2.3 Bits Used for Parity Control and Generation
Bit Name Location Description
Assert SATN/ on
Parity Errors SCSIControl Zero
(SCNTL0),Bit1 Causes the LSI53C875A to automatical ly assert SATN/
when it detects a SCSI parity error while operatingas an
initiator.
Enable Parity
Checking SCSIControl Zero
(SCNTL0),Bit3 Enables the LSI53C875A to checkfor parity errors. The
LSI53C875A checks forodd parity.
Assert Even SCSI
Parity SCSI Control One
(SCNTL1),Bit2 Determines the SCSI parity sense generated by the
LSI53C875A to the SCSI bus.
Disable Halt on
SATN/or a Parity
Error (TargetMode
Only)
SCSI Control One
(SCNTL1),Bit5 Causes the LSI53C875A notto halt operations when a
parity error is detected in targetmode.
Enable Parity Error
Interrupt SCSI Interrupt
Enable Zero
(SIEN0),Bit0
Determines whether the LSI53C875A generatesan
interrupt when it detects a SCSI parity error.
Parity Error SCSIInterrupt
Status Zero
(SIST0),Bit0
This statusbit is set whenever the LSI53C875A detects a
parity error on the SCSI bus.
Status of SCSI
Parity Signal SCSI Status Zero
(SSTAT0),Bit0 Thisstatus bit representsthe active HIGH current state of
the SCSI SDP0 parity signal.
SCSI SDP1 Signal SCSIStatus Two
(SSTAT2),Bit0 Thisbit represents the active HIGH current state of the
SCSI SDP1 parity signal.
LatchedSCSI Parity SSTAT2,Bit 3 and
SCSI Status One
(SSTAT1),Bit3
These bits reflect the SCSI odd parit y signal
corresponding to the datalatched into the SCSI Input
Data Latch (SIDL) register.
Master Parity Error
Enable Chip TestFour
(CTEST4),Bit3 Enables parity checkingduring PCI master data phases.
Master Data Parity
Error DMA Status
(DSTAT),Bit6 Setwhen the LSI53C875A,as a PCI master, detects a
target devicesignaling a parity error during a data phase.
Master Data Parity
Error Interrupt
Enable
DMA Interrupt
Enable (DIEN),
Bit 6
By clearing this bit, a Master Data Parity Er ror does not
cause assertion of INTA/(or INTB/), but the status bit is
set in the DMA Status (DSTAT)register.