24 Parallel SCSI Interface Product Manual, Rev. A )
Table 8: Receive SCSI bus data and information phase DT timing values
[1] SCSI bus timing values specified by the maximum transfer rate for the given range shall apply even if a
slower transfer rate within the given range is negotiated.
[2] See Section 2.6 for measurement points for the timing specifications.
[3] See Section 9.6 in the ANSI SCSI Parallel Interface-5 (SPI-5) specification for examples of how to calcu-
late setup and hold timing.
[4] Calculated assuming timing budget shown in Table 9.
Note. Fast-160 and fast 320 SCSI devices shall not change timing parameters between training or reset
events.
Timing description Reference Type
Timing values for negotiated transfer rate in nanoseconds
unless otherwise noted
[1]
Fast-10 Fast-20 Fast-40 Fast-80
Fast-
160
Fast-
320
ATN receive setup time
2.5.3 min 13.6 7.8 4.9 3.45 3.0 3.0
Flow control receive hold time
2.5.13 min 11.6 5.8 2.9 1.45 3.0 3.0
Flow control receive setup time
2.5.14 min 18.6 12.8 9.9 8.45 3.0 3.0
pCRC receive hold time
2.5.17 min 11.6 5.8 2.9 1.45 N/A N/A
pCRC receive setup time
2.5.18 min 18.6 12.8 9.9 8.45 N/A N/A
Receive assertion period [2]
2.5.30 min 80 40 20 8.5 4.74 1.615
Receive hold time [2] [3]
2.5.31 min 11.6 5.8 2.9 1.45 -0.08 -6.635
Receive negation period [2]
2.5.34 min 80 40 20 8.5 4.74 1.615
Receive setup time [2] [3]
2.5.35 min 11.6 5.8 2.9 1.45 -6.33 -9.76
Receive REQ(ACK) period toler-
ance
2.5.36 min 0.7 0.7 0.7 0.7 0.06 0.06
Receive REQ assertion period
with P_CRCA transitioning
2.5.37 min 85.5 48 32.5 21 N/A N/A
Receive REQ negation period
with P_CRCA transitioning
2.5.38 min 85.5 48 32.5 21 N/A N/A
Receive skew compensation
2.5.39 max N/A N/A N/A N/A N/A N/A
Receive internal hold time [4]
2.5.32 min N/A N/A N/A N/A 0.345 0.032
Receive internal setup time [4]
2.5.33 min N/A N/A N/A N/A 0.345 0.032
Receiver de-skewed data valid
window [4]
2.5.12 min N/A N/A N/A N/A
±2.1 ± 1.1
