Chapter 4
Signal Connections
PCI-4451/4452/4453/4454 User Manual
4-24
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As an output, the GPCTR0_GATE signal reflects the actual GATE signal
connected to general-purpose counter 0. This is true even if the GATE is
externally generated by another PFI signal. This output is set to
high-impedance at startup.
GPCTR0_OUT Signal
This signal is available only as an output on the GPCTR0_OUT pin. The
GPCTR0_OUT signal reflects the terminal count (TC) of general-purpose
counter 0. 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 4-13 shows the timing of the GPCTR0_OUT signal.
Figure 4-13.
GPCTR0_OUT Signal Timing
GPCTR0_UP_DOWN Signal (PCI-4451/4452 Only)
You can input this signal on the DIO6 pin. It is not available as an output
on the I/O connector. The general-purpose counter 0 counts down when
this pin is at a logic low and counts up when it is at a logic high. You can
disable this input so that software can control the up-down functionality
and leave the DIO6 pin free for general use.
GPCTR1_SOURCE Signal (PCI-4451/4452 Only)
Any PFI pin can receive as an input the GPCTR1_SOURCE signal, which
is available as an output on the PFI3/GPCTR1_SOURCE pin.
As an input, the GPCTR1_SOURCE signal is configured in edge-detection
mode. You can select any PFI pin as the source for GPCTR1_SOURCE and
configure the polarity selection for either rising or falling edge.
GPCTR0_SOURCE
GPCTR0_OUT
GPCTR0_OUT
(Toggle output on TC)
(Pulse on TC)
TC
