Seagate Ultra 320, Ultra 160 manual Status phase, Message phase

3.7.3DT DATA OUT phase

The DT DATA OUT phase allows the SCSI target port to request that data be sent from the SCSI initiator device to the SCSI target device using DT data transfers. The target shall assert the MSG signal and negate the C/D and I/O signals during the REQ/ACK handshakes of this phase.

3.7.4ST DATA IN phase

The ST DATA IN phase allows the SCSI target port to request that data be sent to the initiator from the target using ST data transfers. The target shall assert the I/O signal and negate the C/D and MSG signals during the REQ/ACK handshake(s) of this phase.

3.7.5ST DATA OUT phase

The ST DATA OUT phase allows the SCSI target device to request that data be sent from the SCSI initiator device to the target device using ST data transfers. The SCSI target port shall negate the C/D, I/O, and MSG signals during the REQ/ACK handshakes of this phase.

3.8STATUS phase

3.8.1STATUS phase description

The STATUS phase allows the SCSI target device to request that a status byte be sent from the target to the SCSI initiator device.

The SCSI target port shall assert the C/D and I/O signals and negate the MSG signal during the REQ/ACK handshake of this phase.

A QAS-capable SCSI initiator port shall wait a minimum of one QAS non-data phase REQ(ACK) period to assert ACK after detecting the assertion of REQ.

A QAS-capable SCSI initiator port shall assert ACK for a minimum of one QAS non-data phase REQ(ACK) period.

3.8.2STATUS phase exception condition handling

If the initiator detects a parity error on the status byte, the initiator shall create an attention condition. When the target switches to a MESSAGE OUT phase, the initiator should send a SCSI initiator port Detected Error mes- sage (see Section 4.3.5) to the target. This message notifies the target that the Status byte was invalid.

3.9MESSAGE phase

3.9.1MESSAGE phase overview

The MESSAGE phase is a term that references either a MESSAGE IN or a MESSAGE OUT phase. Multiple messages may be sent during either phase. The first byte transferred in either of these phases shall be either

asingle-byte message or the first byte of a multiple-byte message. Multiple-byte messages shall be wholly contained within a single MESSAGE phase.

3.9.2MESSAGE IN phase

The MESSAGE IN phase allows the SCSI target port to request that messages be sent to the SCSI initiator port from the SCSI target port.

The SCSI target port shall assert the C/D, I/O, and MSG signals during the REQ/ACK handshakes of this phase.

A QAS-capable SCSI initiator port shall wait a minimum of one QAS non-data phase REQ(ACK) period to assert ACK after detecting the assertion of REQ.

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