SN75C091A Datasheet, PDF (93/106 Pages) Texas Instruments – SCSI Bus Controller

7.49 timing requirements over recommended operating free-air temperature
and supply voltage ranges
PARAMETER
TEST
CONDITIONS
MIN MAX UNIT
td1 Delay time, REQ low to ACK low
td2 Delay time, REQ high to ACK high
tsu1 Setup time, SDP, SD(0:7) valid before ACK low
td3 Delay time, REQ high to SDP, SD(0:7) invalid
0
ns
0
ns
See Figure 7–27
30
ns
0
ns
7.50 timing characteristics over recommended operating free-air temperature
and supply voltage ranges
PARAMETER
TEST
CONDITIONS
MIN MAX UNIT
td4 Delay time, MSG, C/D valid and I/O high to REQ low
400
ns
td5 Delay time, ACK high to MSG, C/D invalid and I/O low
200
ns
tPLH Propagation delay, low to high, ACK low to REQ high
CL =50 pF,
See Figure 7–27
5
ns
tPHL Propagation delay, high to low, ACK high to REQ low
5
ns
tdis Disable time, SDP, SD(0:7) invalid to I/O high
0
ns
MSG
C/D
I/O
REQ
ACK
tdis
SDP, SD(0:7)
Valid
Valid
td4
td1
tPLH
tsu1
Valid
td5
td2
tPHL
td3
Figure 7–27. SCSI Bus Asynchronous Information Transfer Out (Target)
(INITIATOR TO TARGET)
7–28