Chapter 4
Connecting Signals
©
National Instruments Corporation
4-37
Figure 4-35 shows the timing requirements for GPCTR1_OUT.
Figure 4-35.
GPCTR1_OUT Signal Timing
GPCTR1_UP_DOWN Signal
This signal can be received as an input on the DIO7 pin and is not available
as an output on the I/O connector. General-purpose counter 1 counts down
when this pin is at a logic low and counts up at a logic high. This input can
be disabled so that software can control the up-down functionality and
leave the DIO7 pin free for general use. Figure 4-36 shows the timing
requirements for the GATE and SOURCE input signals and the timing
specifications for the OUT output signals.
Figure 4-36.
GPCTR Timing Summary
GPCTR1_SOURCE
GPCTR1_OUT
(Pulse on TC)
GPCTR1_OUT
(Toggle output on TC)
TC
t
sc
t
sp
t
sp
t
gsu
t
gh
t
gw
t
out
V
IH
V
IL
V
IH
V
IL
V
OH
V
OL
SOURCE
GATE
OUT
Source Clock Period
Source Pulse Width
Gate Setup Time
Gate Hold Time
Gate Pulse Width
Output Delay Time
50 ns minimum
23 ns minimum
10 ns minimum
0 ns minimum
10 ns minimum
80 ns maximum
t
sc
t
sp
t
gsu
t
gh
t
gw
t
out
