comedilib/demo/mmap.c
2001-07-15 22:39:54 +00:00

165 lines
3.1 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 <unistd.h>
#include <sys/mman.h>
#include "examples.h"
int comedi_get_front_count(comedi_t *it, unsigned int subdev);
unsigned int chanlist[256];
void *map;
int prepare_cmd_lib(comedi_t *dev,int subdevice,comedi_cmd *cmd);
int prepare_cmd(comedi_t *dev,int subdevice,comedi_cmd *cmd);
int main(int argc, char *argv[])
{
comedi_t *dev;
comedi_cmd c,*cmd=&c;
int size;
int front, back;
int ret;
int i;
parse_options(argc,argv);
dev = comedi_open(filename);
if(!dev){
comedi_perror(filename);
exit(1);
}
size = comedi_get_buffer_size(dev,subdevice);
fprintf(stderr,"buffer size is %d\n",size);
map=mmap(NULL,size,PROT_READ,MAP_SHARED,comedi_fileno(dev),0);
fprintf(stderr,"map=%p\n",map);
for(i=0;i<n_chan;i++){
chanlist[i]=CR_PACK(channel+i,range,aref);
}
//prepare_cmd_lib(dev,subdevice,cmd);
prepare_cmd(dev,subdevice,cmd);
ret = comedi_command_test(dev,cmd);
ret = comedi_command_test(dev,cmd);
if(ret!=0){
fprintf(stderr,"command_test failed\n");
exit(1);
}
dump_cmd(stderr,cmd);
ret = comedi_command(dev,cmd);
if(ret<0){
comedi_perror("comedi_command");
exit(1);
}
back = 0;
while(1){
front = comedi_get_front_count(dev,subdevice);
if(verbose)fprintf(stderr,"front = %d, back = %d\n",front,back);
if(front<back)break;
if(front==back){
//comedi_poll(dev,subdevice);
usleep(10000);
continue;
}
for(i=back;i<front;i+=sizeof(sampl_t)){
static int col = 0;
printf("%d ",*(sampl_t *)(map+(i&(size-1))));
col++;
if(col==n_chan){
printf("\n");
col=0;
}
}
ret = comedi_mark_buffer_read(dev,subdevice,front-back);
if(ret<0){
comedi_perror("comedi_mark_buffer_read");
break;
}
back = front;
}
return 0;
}
int prepare_cmd_lib(comedi_t *dev,int subdevice,comedi_cmd *cmd)
{
int ret;
ret = comedi_get_cmd_generic_timed(dev,subdevice,cmd,1e9/freq);
if(ret<0){
comedi_perror("comedi_get_cmd_generic_timed\n");
return ret;
}
cmd->chanlist = chanlist;
cmd->chanlist_len = n_chan;
cmd->scan_end_arg = n_chan;
if(cmd->stop_src==TRIG_COUNT)cmd->stop_arg = n_scan;
return 0;
}
int prepare_cmd(comedi_t *dev,int subdevice,comedi_cmd *cmd)
{
memset(cmd,0,sizeof(*cmd));
cmd->subdev = subdevice;
cmd->flags = 0;
cmd->start_src = TRIG_NOW;
cmd->start_arg = 0;
cmd->scan_begin_src = TRIG_TIMER;
cmd->scan_begin_arg = 1e9/freq;
cmd->convert_src = TRIG_TIMER;
cmd->convert_arg = 1;
cmd->scan_end_src = TRIG_COUNT;
cmd->scan_end_arg = n_chan;
cmd->stop_src = TRIG_COUNT;
cmd->stop_arg = n_scan;
cmd->chanlist = chanlist;
cmd->chanlist_len = n_chan;
return 0;
}