Chapter 4
Signal Connections
PCI-4451/4452/4453/4454 User Manual
4-26
www.ni.com
GPCTR1_OUT Signal (PCI-4451/4452 Only)
This signal is available only as an output on the GPCTR1_OUT pin. The
GPCTR1_OUT signal monitors the TC device general-purpose counter 1.
You have two software-selectable output options—pulse on TC and toggle
output polarity on TC. The output polarity is software selectable for both
options. This output is set to high-impedance at startup. Figure 4-15 shows
the timing requirements for the GPCTR1_OUT signal.
Figure 4-15.
GPCTR1_OUT Signal Timing
GPCTR1_UP_DOWN Signal (PCI-4451/4452 Only)
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. You can disable
this input so that software can control the up-down functionality and leave
the DIO7 pin free for general use. Figure 4-16
shows the timing
requirements for the GATE and SOURCE input signals and the timing
specifications for the OUT output signals of your PCI-4451/4452.
GPCTR1_SOURCE
GPCTR1_OUT
GPCTR1_OUT
(Toggle output on TC)
(Pulse on TC)
TC
