LSI 53C875A technical manual Register 0x4A, Register 0x4B

Models: 53C875A

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Register: 0x4A

Response ID Zero (RESPID0)

Read/Write

7

0

RESPID0

x

x

x

x

x

x

x

x

RESPIO0 Response ID Zero[7:0]

RESPID0 and Response ID One (RESPID1) contain the selection or reselection IDs. In other words, these two

8-bit registers contain the ID that the chip responds to on the SCSI bus. Each bit represents one possible ID with the most significant bit of RESPID1 representing ID 15 and the least significant bit of RESPID0 representing ID 0. The SCSI Chip ID (SCID) register still contains the chip ID used during arbitration. The chip can respond to more than one ID because more than one bit can be set in the RESPID1 and RESPID0 registers. However, the chip can arbitrate with only one ID value in the SCID register.

Register: 0x4B

Response ID One (RESPID1)

Read/Write

7

0

RESPID1

x

x

x

x

x

x

x

x

RESPID1 Response ID One[7:0]

Response ID Zero (RESPID0) and RESPID1 contain the selection or reselection IDs. In other words, these two

8-bit registers contain the ID that the chip responds to on the SCSI bus. Each bit represents one possible ID with the most significant bit of RESPID1 representing ID 15 and the least significant bit of RESPID0 representing ID 0. The SCSI Chip ID (SCID) register still contains the chip ID used during arbitration. The chip can respond to more than one ID because more than one bit can be set in the RESPID1 and RESPID0 registers. However, the

4-86Registers

Page 178
Image 178
LSI 53C875A technical manual Register 0x4A, Register 0x4B