- National Instrument DAQ 653X High-Speed Digital I/O Devices for PCI, PXI , CompactPCI, AT, EISA, and PCMCIA Bus Systems 653X

Chapter 3 Timing Diagrams
© National Instruments Corporation 3-37 653X User Manual
Figure 3-34.
Long Pulse Input Timing Diagram
Parameter Description Minimum Maximum
Input Parameters
t
rr*
REQ pulse width 75 —
t
r*r
REQ inactive duration 75 —
t
ar
ACK to next REQ 0 —
t
dir(1)
Input data setup to REQ active
(with REQ-edge latching)
0 —
t
rdi
Input data hold from REQ active
(with REQ-edge latching)
10 —
t
dir(2)
Input data setup to REQ
(with REQ-edge latching disabled)
0 —
t
adi
Input data hold from ACK
(with REQ-edge latching disabled)
0 —
Output Parameters
t
aa*
ACK pulse width 125
1
—
t
r*a*
REQ inactive to ACK inactive 150 —
1
t
aa*
(min.) = 125 + programmable delay
REQ
Input Data Valid
(REQ-edge
latching)
Input Data Valid
(REQ-edge
latching disabled)
t
r*r
t
r*a*
t
dir(2)
t
adi
t
ar
t
aa*
t
rr*
t
rdi
t
dir(1)
ACK
ACK and REQ are shown as active high