LSI53CF92A LSI, LSI53CF92A Datasheet - Page 25

• Manufacturer Part Number: LSI53CF92A
• Manufacturer: LSI

Specifications of LSI53CF92A

• Lead Free Status / RoHS Status: Not Compliant

2.2.2 Bus-Initiated Reselection
If the FSC is selected with ATN/ true and the SCSI-2 bit set, the FSC
examines both the message byte and the ATN/ signal to determine how
many bytes to request. If the first byte is a valid identify message and if
ATN/ goes false after receiving the first byte, the FSC changes to
Command phase. If the first byte is a valid identify message byte
(0x80–0xFF) and ATN/ is still true, it requests two more message bytes.
After requesting the message bytes, the FSC requests Command phase
bytes unless one of the following situations occurs:
All of these conditions cause the FSC to interrupt and stop.
To determine if one of these conditions has occurred, examine the
Sequence Step register.
The CDB always begins at the third or fifth byte in the FIFO, assuming
selection completed normally. The CDB may be 6, 10 or 12 bytes long.
Thus, in SCSI-2, the entire FIFO may be filled if a tagged-queuing,
12-byte command is used.
The FSC allows itself to be reselected as an initiator by a target if it has
previously received the Enable Selection/Reselection command. If the
sequence completes normally, the FIFO has the following information:
The bus ID is always present and is always one byte. It is an unencoded
version of the state of the bus during Reselection phase.
The identify message is always present and is always one byte.
Bus-Initiated Sequences
Copyright © 1995–2002 by LSI Logic Corporation. All rights reserved.
The first byte is not a valid identify message
A parity error is detected
ATN/ goes false between the second and third bytes
ATN/ remains true but the SCSI-2 bit is false.
Bus ID
Identify message
2-5