comedi_digital_trigger_enable_levels — set digital trigger level detection


#include <comedilib.h>
int comedi_digital_trigger_enable_levels(comedi_t * device,
 unsigned int subdevice,
 unsigned int trigger_id,
 unsigned int base_input,
 unsigned int high_level_inputs,
 unsigned int low_level_inputs);




This function enables level detection for a digital trigger on a subdevice. If the subdevice supports several digital triggers, the trigger_id selects one. The high_level_inputs and low_level_inputs parameters are bit fields that enable (1) or disable (0) high and low level detection on a set of (up to) 32 inputs. The least-significant bit corresponds to the input specified by the base_input parameter, with subsequent bits corresponding to subsequent inputs.

Successive calls to this function have an cumulative effect, which allows digital triggers to be set up for more than 32 inputs. There may also be a cumulative effect with calls to comedi_digital_trigger_enable_edges if the digital trigger supports a combination of edge and level triggering. Due to the cumulative effect, it may be necessary to call comedi_digital_trigger_disable to clear the old settings before reconfiguring the digital trigger inputs.

A digital trigger may support edge detection, level detection, both at different times, or both at the same time. If it supports both but not at the same time, configuring level triggers will disable any previous edge triggers, or vice versa.

This function is only useable on subdevices that provide support for the INSN_CONFIG_DIGITAL_TRIG configuration instruction, and only if the digital trigger supports level detection.

Return value

0 on success, -1 on error.