123 lines
3.7 KiB
C
123 lines
3.7 KiB
C
/*
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* NI quadrature encoder example.
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* Part of Comedilib
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*
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* Copyright (c) 2007 Anders Blomdell <anders.blomdell@control.lth.se>
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*
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* This file may be freely modified, distributed, and combined with
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* other software, as long as proper attribution is given in the
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* source code.
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*/
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/*
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* Requirements: A board with a National Instruments general-purpose
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* counter, and comedi driver version 0.7.74 or newer.
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <comedilib.h>
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#include <math.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <getopt.h>
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#include <ctype.h>
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#include "examples.h"
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int ni_gpct_start_encoder(comedi_t *device, unsigned subdevice,
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unsigned int initial_value,
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int a, int b, int z)
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{
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int retval;
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lsampl_t counter_mode;
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retval = comedi_reset(device, subdevice);
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/* set initial counter value by writing to channel 0 */
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retval = comedi_data_write(device, subdevice, 0, 0, 0, initial_value);
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/* set "load a" register to initial_value by writing to channel 1 */
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retval = comedi_data_write(device, subdevice, 1, 0, 0, initial_value);
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/* set "load b" register to initial_value by writing to channel 2 */
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retval = comedi_data_write(device, subdevice, 2, 0, 0, initial_value);
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comedi_set_gate_source(device, subdevice, 0, 0, NI_GPCT_DISABLED_GATE_SELECT);
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comedi_set_gate_source(device, subdevice, 0, 1, NI_GPCT_DISABLED_GATE_SELECT);
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/* note, the comedi_set_other_source calls will fail on 660x boards, since they
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* don't support user selection of the inputs used for the A/B/Z signals. */
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comedi_set_other_source(device, subdevice, 0, NI_GPCT_SOURCE_ENCODER_A, a);
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comedi_set_other_source(device, subdevice, 0, NI_GPCT_SOURCE_ENCODER_B, b);
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comedi_set_other_source(device, subdevice, 0, NI_GPCT_SOURCE_ENCODER_Z, z);
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counter_mode = (NI_GPCT_COUNTING_MODE_QUADRATURE_X4_BITS |
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NI_GPCT_COUNTING_DIRECTION_HW_UP_DOWN_BITS);
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if (z != NI_GPCT_DISABLED_GATE_SELECT) {
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counter_mode |= (NI_GPCT_INDEX_ENABLE_BIT |
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NI_GPCT_INDEX_PHASE_HIGH_A_HIGH_B_BITS);
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}
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retval = comedi_set_counter_mode(device, subdevice, 0, counter_mode);
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if(retval < 0) return retval;
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retval = comedi_arm(device, subdevice, NI_GPCT_ARM_IMMEDIATE);
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if(retval < 0) return retval;
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return 0;
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}
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int main(int argc, char *argv[])
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{
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comedi_t *device = NULL;
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int subdevice = -1;
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int a = NI_GPCT_DISABLED_OTHER_SELECT;
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int b = NI_GPCT_DISABLED_OTHER_SELECT;
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int z = NI_GPCT_DISABLED_OTHER_SELECT;
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unsigned int initial_value = 0;
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int retval;
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{
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int c;
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while (-1 != (c = getopt(argc, argv, "f:s:A:B:Z:I:"))) {
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switch (c) {
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case 'f':
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device = comedi_open(optarg);
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if(!device) {
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comedi_perror(optarg);
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exit(-1);
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}
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break;
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case 's':
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subdevice = strtoul(optarg, NULL, 0);
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break;
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case 'A':
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/* TODO: Should we pass the value directly, i.e. could anybody
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* be interested in values besides PFIx/DISABLED */
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a = NI_GPCT_PFI_OTHER_SELECT(strtoul(optarg, NULL, 0));
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break;
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case 'B':
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/* TODO: Should we pass the value directly, i.e. could anybody
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* be interested in values besides PFIx/DISABLED */
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b = NI_GPCT_PFI_OTHER_SELECT(strtoul(optarg, NULL, 0));
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break;
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case 'Z':
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/* TODO: Should we pass the value directly, i.e. could anybody
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* be interested in values besides PFIx/DISABLED */
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z = NI_GPCT_PFI_OTHER_SELECT(strtoul(optarg, NULL, 0));
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break;
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case 'I':
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initial_value = strtoul(optarg, NULL, 0);
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break;
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}
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}
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}
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/*FIXME: check that device is counter */
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printf("Initiating encoder on subdevice %d.\n", subdevice);
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retval = ni_gpct_start_encoder(device, subdevice, initial_value, a, b, z);
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if(retval < 0) return retval;
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return 0;
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}
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