National Instruments 653X - Manual (Page 85)

Chapter 3 Timing Diagrams
653X User Manual 3-34 ni.com
Figure 3-31. Leading Edge Output Timing Diagram
Note With REQ edge latching disabled (default), output data valid will hold t
rdo
ns after
the REQ edge occurs. With REQ edge latching enabled, that data will be 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 125 —
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