Chapter 4
Signal Connections
©
National Instruments Corporation
4-31
Figure 4-27 shows the timing requirements for the GPCTR0_GATE
signal.
Figure 4-27.
GPCTR0_GATE Signal Timing in Edge-Detection Mode
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
tri-state at startup. Figure 4-28 shows the timing of the GPCTR0_OUT
signal.
Figure 4-28.
GPCTR0_OUT Signal Timing
GPCTR0_UP_DOWN Signal
This signal can be externally input on the DIO6 pin and is not available
as an output on the I/O connector. The general-purpose counter 0 will
count down when this pin is at a logic low and count 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.
Rising-edge
polarity
Falling-edge
polarity
t
w
t
w
= 10 ns minimum
GPCTR0_SOURCE
GPCTR0_OUT
GPCTR0_OUT
(Toggle output on TC)
(Pulse on TC)
TC
PCI_E.book Page 31 Thursday, June 25, 1998 12:55 PM