National Instruments NI 653 Series, User Manual

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Chapter 3 Timing Diagrams
© National Instruments Corporation 3-31 NI 653X User Manual
Figure 3-31. Leading-Edge Output Timing Diagram
Note With REQ-edge latching disabled (default), output data valid is held t
rdo
ns after the
REQ edge occurs. With REQ-edge latching enabled, that data is held for at most t
rdo
ns
after the REQ edge deasserts.
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 —
Output Parameters
t
aa*
ACK pulse width 150 —
t
r*a*
REQ inactive to ACK inactive 150 —
t
r*do
REQ inactive to new output data
(with REQ-edge latching) 0 50
t
rdo
REQ to new output data
(with REQ-edge latching disabled) 0 —
t
doa
Output data valid to ACK
(with REQ-edge latching disabled) 25
1
—
1
t
doa
(min.) = 25 + programmable delay
REQ
Output Data Valid
(REQ-edge
Latching)
Output Data Valid
(REQ-edge
Latching Disabled)
t
r*r
t
r*a*
t
r*do
t
doa
t
ar
t
aa*
t
rr*
ACK
t
rdo
ACK and REQ are shown as active high.