National Instruments 653X Manuale Utente

Pagina di 147
Chapter 3
Timing Diagrams
© National Instruments Corporation
3-37
Figure 3-34.  Long Pulse Input Timing Diagram
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
t
dir(1)
Input data setup to REQ active
(with REQ-edge latching)
0
t
rdi
Input data hold from REQ active
(with REQ-edge latching)
10
t
dir(2)
Input data setup to REQ
(with REQ-edge latching disabled)
0
t
adi
Input data hold from ACK
(with REQ-edge latching disabled)
0
Output Parameters
t
aa*
ACK pulse width
125
1
t
r*a*
REQ inactive to ACK inactive
150
1
 
t
aa*
(min.)
 
= 125 + programmable delay
REQ
Input Data Valid
(REQ-edge
latching)
Input Data Valid
(REQ-edge
latching disabled)
t
r*r
t
r*a*
t
dir(2)
t
adi
t
ar
t
aa*
t
rr*
t
rdi
t
dir(1)
ACK
ACK and REQ are shown as active high