Chapter 3
Timing Diagrams
©
National Instruments Corporation
3-21
Figure 3-19.
Level-ACK Output Timing Diagram
Note
With REQ-edge latching disabled (default), output data valid holds
t
rdo
ns after the
REQ edge is asserted. 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
225
—
t
ra*
REQ to ACK inactive
100
200
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*do
t
ra*
t
doa
t
ar
t
aa*
t
rr*
ACK
t
rdo
t
rdo
ACK and REQ are shown as active high.