National Instruments DAQCard-6533, User Manual

Page: 82 / 152

Chapter 3 Timing Diagrams
NI 653X User Manual 3-26 ni.com
Figure 3-25. Trailing-Edge Output Timing Diagram
Note When REQ-edge latching is disabled (default), output valid data is held t
r*do(1)
ns
after the trailing edge of REQ occurs. With REQ-edge latching enabled, output data will
be at most t
r*do(1)
ns after the trailing edge of REQ occurs.
Parameter Description Minimum Maximum
Input Parameters
t
rr*
REQ pulse width 75 —
t
r*r
REQ inactive duration 75 —
t
a*r*
ACK inactive to next REQ inactive 0 —
Output Parameters
t
aa*
ACK pulse width 225
1
275
2
t
r*do(1)
REQ inactive to new output data
(with REQ-edge latching) 0 50
t
r*do(2)
REQ inactive to new output data
(with REQ-edge latching disabled) 0 —
t
doa
Output data valid to ACK
(with REQ-edge latching disabled) 25 —
1
t
aa*
(min)
= 225 + programmable delay
2
t
aa*
(max) = 275 + programmable delay
REQ
Output Data Valid
(REQ-edge
Latching)
Output Data Valid
(REQ-edge
Latching Disabled)
t
r*r
t
r*do(1)
t
doa
t
aa*
t
a*r*
t
rr*
ACK
t
r*do(2)
ACK and REQ are shown as active high.