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Chapter 3 Software Overview
NI-VXI User Manual 3-58 © National Instruments Corporation
Trigger Configuration Functions
You can use the NI-VXI trigger configuration functions to configure
not only the general settings of the trigger inputs and outputs, but also
the TIC counter and tick timers.
TrigAssertConfig (controller, trigline, mode)
TrigAssertConfig
configures the local triggering generation method
for the TTL/ECL triggers. You can decide on an individual basis
whether to synchronize the triggers to CLK10. You can globally select
the synchronization to be the rising or falling edge of CLK10. In
addition, you can specify the trigger line to partake in automatic
external SEMI-SYNC acknowledgment. In this mode, when a trigger is
sensed on the line, the line is asserted until an external (GPIO) trigger
line which is mapped to the corresponding trigger line is pulsed. You
can also use
AcknowledgeTrig
to manually acknowledge a pending
SEMI-SYNC trigger configured in this fashion.
TrigCntrConfig (controller, mode, source, count)
TrigCntrConfig
configures the TIC chip’s 16-bit counter. You can
use this function to initialize, reload, or disable the current counter
settings. If the counter is initialized, you must call either
SrcTrig
or
EnableTrigSense
to actually start the counter. You can use any
trigger line, CLK10, or EXTCLK as the source of the counter. The
count range is 1 to 65535. You can use the counter to source multiple
sync or multiple semi-sync triggers to one or more trigger lines. You
can also use it to accept multiple sync or multiple semi-sync triggers
from one trigger line. The counter has two outputs: TCNTR and
GCNTR. The TCNTR signal pulses for 100 ns every time a source
pulse occurs. You can use
MapTrigToTrig
to map the TCNTR signal
to one or more trigger lines. The GCNTR signal stays unasserted until
the counter goes from 1 to 0. It then becomes asserted until the counter
is disabled. You can use the
MapTrigToTrig
function to directly map
the GCNTR signal to one or more GPIO lines.
TrigExtConfig (controller, extline, mode)
TrigExtConfig
configures the way the external trigger sources
(General-Purpose Inputs and Outputs, or GPIOs) are configured. The
TIC chip has 10 GPIO lines. Typically, GPIO 0 is connected to the
front panel In connector. GPIO 1 is connected to the front panel Out
connector. GPIO 2 is connected to a direct ECL bypass from the front