SEL

Selected

5

 

This bit is set when the LSI53C810A is selected by

 

 

another SCSI device. The Enable Response to Selection

 

bit must be set in the SCSI Chip ID (SCID) register (and

 

the Response ID (RESPID) register must hold the chip’s

 

ID) for the LSI53C810A to respond to selection attempts.

RSL

Reselected

4

 

This bit is set when the LSI53C810A is reselected by

 

 

another SCSI device. The Enable Response to

 

 

Reselection bit must be set in the SCSI Chip ID (SCID)

 

register (and the Response ID (RESPID) register must

 

 

hold the chip’s ID) for the LSI53C810A to respond to

 

 

reselection attempts.

 

SGE

SCSI Gross Error

3

 

This bit is set when the LSI53C810A encounters a SCSI

 

Gross Error Condition. The following conditions can result

 

in a SCSI Gross Error Condition:

 

 

Data Underflow – reading the SCSI FIFO register

 

 

when no data is present.

 

 

Data Overflow – writing too many bytes to the SCSI

 

FIFO, or the synchronous offset causes overwriting

 

 

the SCSI FIFO.

 

 

Offset Underflow – the LSI53C810A is operating in

 

 

target mode and a SACK/ pulse is received when the

 

outstanding offset is zero.

 

 

Offset Overflow – the other SCSI device sends a

 

 

SREQ/ or SACK/ pulse with data which exceeds the

 

maximum synchronous offset defined by the SCSI

 

 

Transfer (SXFER) register.

 

 

A phase change occurs with an outstanding

 

 

synchronous offset when the LSI53C810A is

 

 

operating as an initiator.

 

 

Residual data in the synchronous data FIFO – a

 

 

transfer other than synchronous data receive is

 

 

started with data left in the synchronous data FIFO.

 

UDC

Unexpected Disconnect

2

 

This bit is set when the LSI53C810A is operating in the

 

initiator mode and the target device unexpectedly

 

 

disconnects from the SCSI bus. This bit is only valid

 

5-52

Operating Registers

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LSI 53C810A technical manual Transfer Sxfer register