6-56 Electrical Specifications
Table 6.42 SCSI-2 Fast Transfers 10.0 Mbytes (8-Bit Transfers) or 20.0 Mbytes(16-Bit Transfers) 40 MHz Clock
Symbol Parameter Min Max Unit
t1Send SREQ/ or SACK/ assertion pulse width 30 ns
t2Send SREQ/ or SACK/ deassertion pulse width 30 ns
t1Receive SREQ/ or SACK/ assertion pulse width 22 ns
t2Receive SREQ/ or SACK/deassertion pulse width 22 ns
t3Send data setup to SREQ/ or SACK/ asserted 24 ns
t4Send data hold from SREQ/ or SACK/asserted 34 ns
t5Receive data setup toSR EQ/or SACK/ asserted 14 ns
t6Receive data holdfrom SREQ/ or SACK/ asserted 24 ns
Table 6.43 Ultra SCSI Transfers 20.0 Mbytes (8-Bit Transfers) or
40.0 Mbytes (16-Bit Transfers) Quadrupled 40 MHz Clock1, 2
1. Transferperiod bits (bits [6:4] in the SCSI Transfer (SXFER) register)aresettozeroandtheExtra
Clock Cycle of Data Setupbit (bit 7 in SCSI Control One (SCNTL1))isset.
2. During Ultra SCSI transfers, the value of the Extend REQ/ACK Fi ltering bit (SCSI TestTwo
(STEST2), bit 1) has no effect.
Symbol Parameter Min Max Unit
t1Send SREQ/ or SACK/ assertion pulse width 15 ns
t2Send SREQ/ or SACK/ deassertion pulse width 15 ns
t1Receive SREQ/ or SACK/ assertion pulse width 11 ns
t2Receive SREQ/ or SACK/deassertion pulse width 11 ns
t3Send data setup to SREQ/ or SACK/ asserted 12 ns
t4Send data hold from SREQ/ or SACK/asserted 17 ns
t5Receive data setup toSR EQ/or SACK/ asserted 6 ns
t6Receive data holdfrom SREQ/ or SACK/ asserted 11 ns