Seagate Ultra 160, Ultra 320 manual Wrflow, Rdstrm, RTI Retain Training Information, Pcompen

Table 20 defines valid combinations of HOLD_MCS and other fields.

2.12.8.5WR_FLOW

The SCSI initiator port shall set WR_FLOW to one to indicate that the SCSI target port should enable write flow control during write streaming. In response, the SCSI target port shall set WR_FLOW to one if it is capable of write flow control and zero if it is not.

The SCSI initiator port shall set WR_FLOW to zero to indicate that the SCSI target port shall disable write flow control during write streaming. In response, the SCSI target port shall set WR_FLOW to zero. Write streaming and write flow control only occurs during information unit transfers.

Table 20 defines valid combinations of WR_FLOW and other fields.

2.12.8.6RD_STRM

The SCSI initiator port shall set RD_STRM to one to indicate that the SCSI target port should enable read streaming and read flow control. In response, the SCSI target port shall set RD_STRM to one if it is capable of read streaming and read flow control and zero if it is not.

The SCSI initiator port shall set RD_STRM to zero to indicate that the SCSI target port shall disable read streaming and read flow control. In response, the SCSI target port shall set RD_STRM to zero. Read stream- ing and read flow control only occur during information unit transfers.

Table 20 defines valid combinations of RD_STRM and other fields.

2.12.8.7RTI (Retain Training Information)

The SCSI initiator port shall set RTI to one to indicate it is capable of saving paced data transfer training infor- mation and to indicate that the SCSI target port does not need to retrain on each connection. In response, the SCSI target port shall set RTI to one if it is capable of saving paced data transfer training information and zero if it is not.

The SCSI initiator port shall set RTI to zero to indicate it is not capable of saving paced data transfer training information and to indicate the SCSI target port shall retrain on each connection. In response, the SCSI target port shall set RTI to zero.

Table 20 defines valid combinations of RTI and other fields. For negotiated transfer periods slower than Fast- 160 the RTI bit shall be set to zero.

2.12.8.8PCOMP_EN

The SCSI initiator port shall set PCOMP_EN to one to indicate that the SCSI target port shall enable precom- pensation on all signals transmitted during DT DATA phases. The SCSI initiator port shall set PCOMP_EN to zero to indicate that the SCSI target port shall disable precompensation.

The SCSI target port shall set PCOMP_EN to one to indicate that the SCSI initiator port shall enable precom- pensation on all signals transmitted during DT DATA phases. The SCSI target port shall set PCOMP_EN to zero to indicate that the SCSI initiator port shall disable precompensation.

Table 20 defines valid combinations of PCOMP_EN and other fields. Ports that support Fast-160 shall support enabling and disabling precompensation of their drivers. For negotiated transfer periods slower than Fast-160 the PCOMP_EN bit shall be set to zero.

Note. Unlike other fields and bits in the PPR message the PCOMP_EN bit is not a negotiated value; instead, it instructs the receiving SCSI device as to whether or not precompensation is to be disabled or enabled. Because of this, precompensation may be enabled on one of the SCSI devices and disabled on the other SCSI device at the completion of a successful PPR negotiation.

Parallel SCSI Interface Product Manual, Rev. A ) 47