Register: 0x4E (0xCE)

SCSI Test Two (STEST2)

Read/Write

7

6

5

4

 

3

2

1

0

 

SCE

ROF

R

SLB

 

SZM

R

EXT

LOW

 

0

0

x

0

 

0

x

0

0

 

 

 

 

 

 

 

 

 

 

SCE

SCSI Control Enable

 

 

 

7

Setting this bit allows assertion of all SCSI control and data lines through the SCSI Output Control Latch (SOCL) and SCSI Output Data Latch (SODL) registers regardless of whether the LSI53C810A is configured as a target or initiator.

Note:

Do not set this bit during normal operation, since it could

 

 

cause contention on the SCSI bus. It is included for

 

 

diagnostic purposes only.

 

ROF

Reset SCSI Offset

6

 

Setting this bit clears any outstanding synchronous

 

 

SREQ/SACK offset. Set this bit if a SCSI gross error

 

 

condition occurs and to clear the offset when a

 

 

synchronous transfer does not complete successfully.

 

 

The bit automatically clears itself after resetting the

 

 

synchronous offset.

 

R

Reserved

5

SLB

SCSI Loopback Mode

4

 

Setting this bit allows the LSI53C810A to perform SCSI

 

loopback diagnostics. That is, it enables the SCSI core to

 

simultaneously perform as both the initiator and the

 

 

target.

 

SZM

SCSI High Impedance Mode

3

 

Setting this bit places all the open drain 48 mA SCSI

 

 

drivers into a high impedance state. This is to allow

 

 

internal loopback mode operation without affecting the

 

 

SCSI bus.

 

5-62

Operating Registers

Page 136
Image 136
LSI 53C810A technical manual Register 0x4E 0xCE, Sce, Rof, Slb, Szm