National Instruments 653X Manuale Utente
Chapter 3
Timing Diagrams
3-28
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Figure 3-25. Trailing Edge Output Timing Diagram
Note
When REQ-edge latching is disabled (default), output data valid will be held
t
r*do(1)
ns after the trailing edge of REQ occurs. With REQ-edge latching enabled, output
data will be held 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)
(with REQ-edge latching)
0
50
t
r*do(2)
REQ inactive to new output data
(with REQ-edge latching disabled)
(with REQ-edge latching disabled)
0
—
t
doa
Output data valid to ACK
(with REQ-edge latching disabled)
(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