Mode 2 Bidirectional Timing - National Instruments Low-Cost Multifunction I/O Board for ISA Lab-PC+ User Manual

Signal Connections

Mode 2 Bidirectional Timing

The timing specifications for bidirectional transfers in Mode 2 are as follows:
WR *
OBF *
INTR
ACK *
STB *
IBF
RD *
DATA
Name Description
T1 WR* = 1 to OBF* = 0
T2 Data before STB* = 1
T3 STB* pulse width
T4 STB* = 0 to IBF = 1
T5 Data after STB* = 1
T6 ACK* = 0 to OBF = 1
T7 ACK* pulse width
T8 ACK* = 0 to output
T9 ACK* = 1 to output float
T10 RD* = 1 to IBF = 0
All timing values are in nanoseconds.
Lab-PC+ User Manual
T1
T3
T4
T2 T5
Minimum
500
180
300
3-20
T6
T7
T8 T9
–
0
–
–
–
20
–
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Chapter 3
T10
Maximum
650
–
–
300
–
350
–
300
250
300