Register: 0x04

SCSI Chip ID (SCID)

Read/Write

7

6

5

4

 

3

 

 

 

 

 

0

R

RRE

 

SRE

R

 

 

 

 

ENC

 

x

0

 

0

x

 

0

 

0

 

0

 

0

R

 

Reserved

 

 

 

 

 

 

 

 

7

RRE

 

Enable Response to Reselection

 

 

 

6

 

 

When this bit is set, the LSI53C875A is enabled to

 

 

 

respond to bus-initiated reselection at the chip ID in the

 

 

Response ID Zero (RESPID0) and Response ID One

 

 

(RESPID1) registers. Note that the chip does not

 

 

 

automatically reconfigure itself to the initiator mode as a

 

 

result of being reselected.

 

 

 

 

 

SRE

 

Enable Response to Selection

 

 

 

 

5

 

 

When this bit is set, the LSI53C875A is able to respond

 

 

to bus-initiated selection at the chip ID in the RESPID0

 

 

and RESPID1 registers. Note that the chip does not

 

 

automatically reconfigure itself to target mode as a result

 

 

of being selected.

 

 

 

 

 

 

 

R

 

Reserved

 

 

 

 

 

 

 

 

4

ENC

 

Encoded Chip SCSI ID

 

 

 

 

 

 

[3:0]

 

 

These bits are used to store the LSI53C875A encoded

 

 

SCSI ID. This is the ID which the chip asserts when

 

 

arbitrating for the SCSI bus. The IDs that the

 

 

 

LSI53C875A responds to when selected or reselected

 

 

are configured in the Response ID Zero (RESPID0) and

 

 

Response ID One (RESPID1) registers. The priority of

 

 

the 16 possible IDs, in descending order is:

 

 

 

 

 

 

 

 

 

 

 

 

 

Highest

 

 

 

Lowest

 

7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8

4-30Registers

Page 122
Image 122
LSI 53C875A technical manual Rre, Sre, Enc