added memory mapped ao waveform demo (untested)
This commit is contained in:
Frank Mori Hess
parent
9f6b16e004
commit
99c8d0b5f1
2 changed files with 186 additions and 1 deletions
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@ -1,6 +1,6 @@
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noinst_PROGRAMS = \
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antialias ao_waveform apply_cal cmd dio eeprom_dump info \
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antialias ao_waveform ao_mmap apply_cal cmd dio eeprom_dump info \
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inp inpn insn ledclock mmap outp poll receiver select \
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sender sigio sv tut1 tut2
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@ -14,6 +14,10 @@ ao_waveform_SOURCES = ao_waveform.c common.c
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ao_waveform_CFLAGS = $(COMEDILIB_CFLAGS)
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ao_waveform_LDADD = $(COMEDILIB_LIBS)
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ao_mmap_SOURCES = ao_mmap.c common.c
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ao_mmap_CFLAGS = $(COMEDILIB_CFLAGS)
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ao_mmap_LDADD = $(COMEDILIB_LIBS)
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apply_cal_SOURCES = apply_cal.c common.c
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apply_cal_CFLAGS = $(COMEDILIB_CFLAGS)
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apply_cal_LDADD = $(COMEDILIB_LIBS)
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181
demo/ao_mmap.c
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181
demo/ao_mmap.c
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@ -0,0 +1,181 @@
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/*
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* Asynchronous Analog Output Example
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* Part of Comedilib
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*
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* Copyright (c) 1999,2000 David A. Schleef <ds@schleef.org>
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* Copyright (c) 2005 Frank Mori Hess <fmhess@@users.sourceforge.net>
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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: Analog output device capable of
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* asynchronous commands.
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*
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* This demo uses an analog output subdevice with an
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* asynchronous command to generate a waveform. The
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* waveform in this example is a sine wave (surprise!).
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* The waveform data is passed to comedi through
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* a memory mapping (as opposed to using write()).
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* The entire buffer is filled once with one period
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* of the waveform.
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*/
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#include <stdio.h>
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#include <comedilib.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.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 <math.h>
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#include <string.h>
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#include <sys/mman.h>
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#include "examples.h"
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static int comedi_internal_trigger(comedi_t *dev, unsigned int subd, unsigned int trignum)
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{
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comedi_insn insn;
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lsampl_t data[1];
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memset(&insn, 0, sizeof(comedi_insn));
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insn.insn = INSN_INTTRIG;
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insn.subdev = subd;
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insn.data = data;
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insn.n = 1;
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data[0] = trignum;
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return comedi_do_insn(dev, &insn);
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}
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static void write_waveform(sampl_t *buffer, int size, double amplitude, double offset, int maxdata)
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{
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int i;
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for(i = 0; i < size; ++i)
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{
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double temp = (amplitude / 2.) * sin((2. * M_PI * i) / size) + offset;
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if(temp < 0.) temp = 0.;
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if(temp > maxdata) temp = maxdata;
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buffer[i] = (sampl_t)temp;
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}
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}
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int main(int argc, char *argv[])
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{
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comedi_cmd cmd;
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int err;
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int n,m;
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int total=0;
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comedi_t *dev;
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unsigned int chanlist[16];
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unsigned int maxdata;
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comedi_range *rng;
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int ret;
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int size;
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sampl_t *map;
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/* peak-to-peak amplitude, in DAC units (i.e., 0-4095) */
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double amplitude;
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/* offset, in DAC units */
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double offset;
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int subdevice;
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parse_options(argc,argv);
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/* Force n_chan to be 1 */
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n_chan = 1;
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dev = comedi_open(filename);
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if(dev == NULL){
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fprintf(stderr, "error opening %s\n", filename);
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return -1;
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}
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subdevice = comedi_find_subdevice_by_type(dev,COMEDI_SUBD_AO,0);
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maxdata = comedi_get_maxdata(dev,subdevice,0);
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rng = comedi_get_range(dev,subdevice,0,0);
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offset = (double)comedi_from_phys(0.0, rng, maxdata);
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amplitude = (double)comedi_from_phys(1.0, rng, maxdata) - offset;
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memset(&cmd,0,sizeof(cmd));
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cmd.subdev = subdevice;
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cmd.flags = 0;
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cmd.start_src = TRIG_INT;
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cmd.start_arg = 0;
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cmd.scan_begin_src = TRIG_TIMER;
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cmd.scan_begin_arg = 1e9/freq;
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cmd.convert_src = TRIG_NOW;
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cmd.convert_arg = 0;
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cmd.scan_end_src = TRIG_COUNT;
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cmd.scan_end_arg = n_chan;
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cmd.stop_src = TRIG_NONE;
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cmd.stop_arg = 0;
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cmd.chanlist = chanlist;
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cmd.chanlist_len = n_chan;
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chanlist[0] = CR_PACK(channel,range,aref);
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dump_cmd(stdout,&cmd);
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err = comedi_command_test(dev, &cmd);
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if (err < 0) {
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comedi_perror("comedi_command_test");
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exit(1);
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}
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err = comedi_command_test(dev, &cmd);
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if (err < 0) {
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comedi_perror("comedi_command_test");
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exit(1);
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}
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if ((err = comedi_command(dev, &cmd)) < 0) {
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comedi_perror("comedi_command");
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exit(1);
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}
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size = comedi_get_buffer_size(dev, subdevice);
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fprintf(stderr, "buffer size is %d\n", size);
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map = mmap(NULL, size, PROT_WRITE, MAP_SHARED, comedi_fileno(dev), 0);
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if(map == MAP_FAILED)
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{
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perror("mmap");
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exit(1);
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}
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write_waveform(map, size, amplitude, offset, maxdata);
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if(msync(map, size, MS_SYNC) < 0)
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{
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perror("msync");
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exit(1);
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}
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ret = comedi_internal_trigger(dev, subdevice, 0);
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if(ret<0){
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comedi_perror("comedi_internal_trigger\n");
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exit(1);
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}
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while(1){
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int bytes_marked = comedi_get_buffer_contents(dev,subdevice);
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if(bytes_marked < 1)
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{
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comedi_perror("comedi_get_buffer_contents");
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exit(1);
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}
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int bytes_unmarked = size - bytes_marked;
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// this keeps comedi from reporting a buffer underrun
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if(comedi_mark_buffer_written(dev, subdevice, bytes_unmarked) < 0)
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{
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comedi_perror("comedi_mark_buffer_written");
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exit(1);
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}
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}
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return 0;
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}
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