Avago Technologies LSI53C896 - Manual (Page 137)

SCSI Registers 4-25
Version 3.3 Copyright © 1998–2003 by LSI Logic Corporation. All rights reserved.
DHP Disable Halt on Parity Error or ATN (Target Only) 5
The DHP bit is only defined for the target mode. When
this bit is cleared, the LSI53C896 SCSI function halts the
SCSI data transfer when a parity error is detected or
when the SATN/ signal is asserted. If SATN/ or a parity
error is received in the middle of a data transfer, the
LSI53C896 SCSI function may transfer up to three
additional bytes before halting to synchronize between
internal core cells. During synchronous operation, the
LSI53C896 SCSI function transfers data until there are
no outstanding synchronous offsets. If the LSI53C896
SCSI function is receiving data, any data residing in the
DMA FIFO is sent to memory before halting.
When this bit is set, the LSI53C896 SCSI function does
not halt the SCSI transfer when SATN/ or a parity error
is received.
CON Connected 4
This bit is automatically set any time the LSI53C896
SCSI function is connected to the SCSI bus as an initiator
or as a target. It is set after the LSI53C896 SCSI function
successfully completes arbitration or when it has
responded to a bus initiated selection or reselection. This
bit is also set after the chip wins simple arbitration when
operating in low level mode. When this bit is cleared, the
LSI53C896 SCSI function is not connected to the
SCSI bus.
The CPU can force a connected or disconnected
condition by setting or clearing this bit. This feature is
used primarily during loopback mode.
RST Assert SCSI RST/ Signal 3
Setting this bit asserts the SRST/ signal. The SRST/
output remains asserted until this bit is cleared. The
25
µ
s minimum assertion time defined in the SCSI
specification must be timed out by the controlling
microprocessor or a SCRIPTS loop.
AESP Assert Even SCSI Parity (Force Bad Parity) 2
When this bit is set, the LSI53C896 SCSI function
asserts even parity. It forces a SCSI parity error on each
byte sent to the SCSI bus from the chip. If parity checking
is enabled, then the LSI53C896 SCSI function checks