comedilib/demo/mmap.c

262 lines
5.9 KiB
C

/*
* Example of using commands - asynchronous input
* Part of Comedilib
*
* Copyright (c) 1999,2000 David A. Schleef <ds@schleef.org>
*
* This file may be freely modified, distributed, and combined with
* other software, as long as proper attribution is given in the
* source code.
*/
/*
* An example for directly using Comedi commands. Comedi commands
* are used for asynchronous acquisition, with the timing controlled
* by on-board timers or external events.
*/
#include <stdio.h>
#include <comedilib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <getopt.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include "examples.h"
#define N_SCANS 10
#define N_CHANS 16
double freq = 1000;
#define BUFSZ 1000
char buf[BUFSZ];
sampl_t *map;
void do_cmd_1(comedi_t *dev);
void do_cmd_2(comedi_t *dev);
void do_cmd(comedi_t *dev,comedi_cmd *cmd);
int main(int argc, char *argv[])
{
char *fn = NULL;
comedi_t *dev;
fn = "/dev/comedi0";
dev = comedi_open(fn);
if(!dev){
perror(fn);
exit(1);
}
fcntl(comedi_fileno(dev),F_SETFL,O_NONBLOCK);
map=mmap(NULL,0x1000,PROT_READ,MAP_SHARED,comedi_fileno(dev),0);
printf("map=%p\n",map);
do_cmd_1(dev);
return 0;
}
void do_cmd(comedi_t *dev,comedi_cmd *cmd)
{
int total=0;
int ret;
int go;
int i;
ret = comedi_command_test(dev,cmd);
printf("test ret=%d\n",ret);
if(ret<0){
printf("errno=%d\n",errno);
comedi_perror("comedi_command_test");
return;
}
dump_cmd(cmd);
ret = comedi_command_test(dev,cmd);
printf("test ret=%d\n",ret);
if(ret<0){
printf("errno=%d\n",errno);
comedi_perror("comedi_command_test");
return;
}
dump_cmd(cmd);
ret = comedi_command(dev,cmd);
printf("ret=%d\n",ret);
if(ret<0){
printf("errno=%d\n",errno);
comedi_perror("comedi_command");
return;
}
go=1;
while(go){
ret=read(comedi_fileno(dev),buf,BUFSZ);
if(ret<0){
if(errno==EAGAIN){
usleep(10000);
}else{
go = 0;
perror("read");
}
}else if(ret==0){
go = 0;
}else{
total+=ret;
printf("read %d %d\n",ret,total);
}
}
for(i=0;i<100;i++){
printf("%d\n",map[i]);
}
}
/*
* This part of the demo measures channels 1, 2, 3, 4 at a rate of
* 10 khz, with the inter-sample time at 10 us (100 khz). The number
* of scans measured is 10. This is analogous to the old mode2
* acquisition.
*/
void do_cmd_1(comedi_t *dev)
{
comedi_cmd cmd;
unsigned int chanlist[4];
memset(&cmd,0,sizeof(cmd));
/* the subdevice that the command is sent to */
cmd.subdev = subdevice;
/* flags */
cmd.flags = 0;
/* each event requires a trigger, which is specified
by a source and an argument. For example, to specify
an external digital line 3 as a source, you would use
src=TRIG_EXT and arg=3. */
/* In this case, we specify using TRIG_NOW to start
* acquisition immediately when the command is issued.
* The argument of TRIG_NOW is "number of nsec after
* NOW", but no driver supports it yet. Also, no driver
* currently supports using a start_src other than
* TRIG_NOW. */
cmd.start_src = TRIG_NOW;
cmd.start_arg = 0;
/* The timing of the beginning of each scan is controlled
* by scan_begin. TRIG_TIMER specifies that scan_start
* events occur periodically at a rate of scan_begin_arg
* nanoseconds between scans. */
cmd.scan_begin_src = TRIG_TIMER;
cmd.scan_begin_arg = 100000; /* in ns */
/* The timing between each sample in a scan is controlled
* by convert. Like above, TRIG_TIMER specifies that
* convert events occur periodically at a rate of convert_arg
* nanoseconds between scans. */
cmd.convert_src = TRIG_TIMER;
cmd.convert_arg = 10000; /* in ns */
/* The end of each scan is almost always specified using
* TRIG_COUNT, with the argument being the same as the
* number of channels in the chanlist. You could probably
* find a device that allows something else, but it would
* be strange. */
cmd.scan_end_src = TRIG_COUNT;
cmd.scan_end_arg = 4; /* number of channels */
/* The end of acquisition is controlled by stop_src and
* stop_arg. The src will typically be TRIG_COUNT or
* TRIG_NONE. Specifying TRIG_COUNT will stop acquisition
* after stop_arg number of scans, or TRIG_NONE will
* cause acquisition to continue until stopped using
* comedi_cancel(). */
#if 1
cmd.stop_src = TRIG_COUNT;
cmd.stop_arg = 100;
#else
cmd.stop_src = TRIG_NONE;
cmd.stop_arg = 0;
#endif
/* the channel list determined which channels are sampled.
In general, chanlist_len is the same as scan_end_arg. Most
boards require this. */
cmd.chanlist = chanlist;
cmd.chanlist_len = 4;
chanlist[0]=CR_PACK(0,range,aref);
chanlist[1]=CR_PACK(1,range,aref);
chanlist[2]=CR_PACK(2,range,aref);
chanlist[3]=CR_PACK(3,range,aref);
do_cmd(dev,&cmd);
}
void do_cmd_2(comedi_t *dev)
{
comedi_cmd cmd;
unsigned int chanlist[4];
memset(&cmd,0,sizeof(cmd));
/* the subdevice that the command is sent to */
cmd.subdev = subdevice;
/* flags */
cmd.flags = 0;
/* each event requires a trigger, which is specified
by a source and an argument. For example, to specify
an external digital line 3 as a source, you would use
src=TRIG_EXT and arg=3. */
cmd.start_src = TRIG_NOW;
cmd.start_arg = 0;
cmd.scan_begin_src = TRIG_TIMER;
cmd.scan_begin_arg = 1; /* in ns */
cmd.convert_src = TRIG_TIMER;
cmd.convert_arg = 1; /* in ns */
cmd.scan_end_src = TRIG_COUNT;
cmd.scan_end_arg = 4; /* number of channels */
#if 1
cmd.stop_src = TRIG_COUNT;
cmd.stop_arg = 100;
#else
cmd.stop_src = TRIG_NONE;
cmd.stop_arg = 0;
#endif
/* the channel list determined which channels are sampled.
In general, chanlist_len is the same as scan_end_arg. Most
boards require this. */
cmd.chanlist = chanlist;
cmd.chanlist_len = 4;
chanlist[0]=CR_PACK(0,range,aref);
chanlist[1]=CR_PACK(1,range,aref);
chanlist[2]=CR_PACK(2,range,aref);
chanlist[3]=CR_PACK(3,range,aref);
do_cmd(dev,&cmd);
}