User manual

Series 3700 System Switch/Multimeter Reference Manual Section 13: Instrument Control Library (ICL)
3700S-901-01 Rev. C / July 2008 13-89
digio.trigger[N].mode
Usage
To read the trigger mode:
tmode = digio.trigger[N].mode
To write the trigger mode:
digio.trigger[N].mode = tmode
N: Digital I/O trigger line 1 to 14
Set tmode to one of the following values:
digio.TRIG_BYPASS or 0: Allow direct control of the line.
digio.TRIG_FALLING or 1: Detect falling edge triggers as input. Assert a TTL-low
pulse for output.
digio.TRIG_RISING or 2: Use digio.TRIG_RISINGA if the line is in the high output
state. Use digio.TRIG_RISINGM if the line is in the low output state.
digio.TRIG_EITHER or 3: Detect rising or falling edge triggers as input. Assert a TTL-
low pulse for output.
digio.TRIG_SYNCHRONOUSA or 4: Detect falling edge triggers as input and
automatically latch and drive them low when detected. Release a latched line for
output.
digio.TRIG_SYNCHRONOUS or 5: Detect falling edge triggers as input and latch
them low. Assert a TTL-low pulse for output.
digio.TRIG_SYNCHRONOUSM or 6: Detect rising edge triggers as input. Assert a
TTL-low pulse for output.
digio.TRIG_RISINGA or 7: Detect rising edge triggers as input. Assert a TTL-low
pulse for output.
digio.TRIG_RISINGM or 8: Assert a TTL-high pulse for output. Input edge detection is
not possible in this mode.
Remarks
The default trigger mode for a line will be TRIG_BYPASS. In this mode, the line can be
directly controlled as a digital I/O line. When programmed to any other mode, the
output state of the I/O line is controlled by the trigger logic and the user specified
output state of the line will be ignored.
For compatibility with older firmware, when the trigger mode is set to TRIG_RISING,
the user specified output state of the line will be examined. If the output state selected
when the mode is changed is high, the actual mode used will be TRIG_RISINGA. If
the output state selected when the mode is changed is low, the actual mode used will
be TRIG_RISINGM.
TRIG_SYNCHRONOUS is provided for compatibility with older firmware. Either
TRIG_SYNCHRONOUSA or TRIG_SYNCHRONOUSM should be used instead.
tmode can be expressed as a number or as one of the pre-defined constants (see
the "Usage" section above).
When reading the trigger mode, it is returned as a number with the modes noted,
tmode is defined.
Example
To set the trigger mode for I/O line 4 to TRIG_RISING:
digio.trigger[4].mode = 2