National Instruments 3.21E+04 用户手册
Chapter 4 Signal Connections
National Instruments Corporation
4-51
AT-MIO/AI E Series User Manual
GPCTR1_UP_DOWN Signal
This signal can be externally 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 4-37
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 4-37
shows the timing requirements for the GATE and SOURCE input
signals and the timing specifications for the OUT output signals of your
AT E Series board.
signals and the timing specifications for the OUT output signals of your
AT E Series board.
Figure 4-37. GPCTR Timing Summary
SOURCE
V
IH
V
IL
V
IH
V
IL
t
sc
t
sp
t
sp
t
gsu
t
gh
t
gw
GATE
t
out
OUT
V
OH
V
OL
sc
t
t
t
t
t
t
t
t
t
t
50 ns minimum
sp
23 ns minimum
gsu
10 ns minimum
gh
0 ns minimum
gw
10 ns minimum
out
80 ns maximum
Source Clock Period
Source Pulse Width
Gate Setup Time
Gate Hold Time
Gate Pulse Width
Output Delay Time
Source Pulse Width
Gate Setup Time
Gate Hold Time
Gate Pulse Width
Output Delay Time