Seagate Ultra 160 manual DT Data in phase training pattern, Start of section a, Start of section B

If the retain training information is enabled, a training pattern shall be transferred at the start of the first DT DATA phase for each data transfer direction after the retain training information is enabled. The SCSI device shall save training configuration values for each I_T nexus that has negotiated to retain training information. The SCSI device shall use the saved training configuration values for all paced transfers. The SCSI target port may retrain an I_T nexus if it determines the training configuration values are invalid, without having to renego- tiate the retain training information protocol option.

Note. The training configuration values are vendor specific.

If the retain training information is enabled and a port changes from a SCSI initiator port to a SCSI target port that SCSI target port shall retrain if the saved training configuration values were saved while the port was a SCSI initiator port.

The training pattern for a DATA IN phase shall conform to Section 3.5.3.1.1. The training pattern for a DATA OUT phase shall conform to Section 3.5.3.1.2. The receiving SCSI device shall use some or all elements of the training pattern to achieve deskewing. The transmitting SCSI device shall not make an intentional shift in rela- tive timing between the data bus signals and the REQ or ACK signal during the DT data phase.

Note. The requirement to not intentionally change relative timing does not include the effects of ISI, noise, or jitter.

The training pattern consists of three sections: A, B, and C. Each section contains a different pattern that may be used to train circuits within a receiver.

3.5.3.1.1DT DATA IN phase training pattern

The SCSI target port shall indicate a training pattern is going to occur on a DT DATA IN phase by:

1.releasing SEL for a minimum of two system deskew delays;

2.asserting the SEL signal a minimum of two system deskew delays; and

3.then asserting the REQ signal.

The SCSI target port shall begin the section A of its training pattern only after all the signal restrictions between information transfers phases listed in Section 3.10 or the signal restrictions between a RESELECTION phase and a DT DATA IN phase listed in Section 3.3 are met. The SCSI target port shall transmit the following training pattern:

Start of section A

1.if precompensation is enabled, then set the drivers to the strong driver state;

2.simultaneously assert REQ, P1, P_CRCA, and DB(15-0) signals;

3.wait the equivalent of 32 transfer periods (e.g., 200 ns at Fast-160);

4.simultaneously negate REQ, P1, P_CRCA, and DB(15-0) signals;

5.wait the equivalent of 32 transfer periods;

6.set precompensation to negotiated state;

7.negate SEL signal;

8.simultaneously assert and negate REQ, P1, P_CRCA, and DB(15-0) signals at the negotiated transfer period for 800 ns, (e.g., the equivalent of 128 transfer periods at Fast-160);

Start of section B

1.wait the equivalent of 192 transfer periods from the first assertion of REQ in step 2 of section A (e.g., 1200 ns at Fast-160);

2.keep the P1, P_CRCA, and DB(15-0) signals negated while continuing to assert and negate REQ at the negotiated transfer period for the equivalent of 8 transfer periods (e.g., 50 ns at Fast-160);

3.keep the P1, P_CRCA, DT(15-0), and REQ signals negated for the equivalent of 8 additional transfer periods;

Parallel SCSI Interface Product Manual, Rev. A 69