demo/mmap.c

   1 /*
   2  * Example of using commands - asynchronous input
   3  * Part of Comedilib
   4  *
   5  * Copyright (c) 1999,2000 David A. Schleef <ds@schleef.org>
   6  *
   7  * This file may be freely modified, distributed, and combined with
   8  * other software, as long as proper attribution is given in the
   9  * source code.
  10  */
  11
  12 /*
  13  * An example for directly using Comedi commands.  Comedi commands
  14  * are used for asynchronous acquisition, with the timing controlled
  15  * by on-board timers or external events.
  16  */
  17
  18 #include <stdio.h>
  19 #include <comedilib.h>
  20 #include <fcntl.h>
  21 #include <unistd.h>
  22 #include <stdlib.h>
  23 #include <errno.h>
  24 #include <unistd.h>
  25 #include <sys/mman.h>
  26 #include <string.h>
  27 #include "examples.h"
  28
  29 unsigned int chanlist[256];
  30
  31 void *map;
  32
  33 int prepare_cmd_lib(comedi_t *dev,int subdevice,comedi_cmd *cmd);
  34 int prepare_cmd(comedi_t *dev,int subdevice,comedi_cmd *cmd);
  35
  36
  37 int main(int argc, char *argv[])
  38 {
  39         comedi_t *dev;
  40         comedi_cmd c,*cmd=&c;
  41         int size;
  42         int front, back;
  43         int ret;
  44         int i;
  45
  46         parse_options(argc,argv);
  47
  48         dev = comedi_open(filename);
  49         if(!dev){
  50                 comedi_perror(filename);
  51                 exit(1);
  52         }
  53
  54         size = comedi_get_buffer_size(dev,subdevice);
  55         fprintf(stderr,"buffer size is %d\n",size);
  56
  57         map=mmap(NULL,size,PROT_READ,MAP_SHARED,comedi_fileno(dev),0);
  58         fprintf(stderr,"map=%p\n",map);
  59         if( map == MAP_FAILED ){
  60                 perror( "mmap" );
  61                 exit(1);
  62         }
  63
  64         for(i=0;i<n_chan;i++){
  65                 chanlist[i]=CR_PACK(channel+i,range,aref);
  66         }
  67
  68         //prepare_cmd_lib(dev,subdevice,cmd);
  69         prepare_cmd(dev,subdevice,cmd);
  70
  71         ret = comedi_command_test(dev,cmd);
  72
  73         ret = comedi_command_test(dev,cmd);
  74
  75         if(ret!=0){
  76                 fprintf(stderr,"command_test failed\n");
  77                 exit(1);
  78         }
  79
  80         dump_cmd(stderr,cmd);
  81
  82         ret = comedi_command(dev,cmd);
  83         if(ret<0){
  84                 comedi_perror("comedi_command");
  85                 exit(1);
  86         }
  87
  88         front = 0;
  89         back = 0;
  90         while(1){
  91                 front += comedi_get_buffer_contents(dev,subdevice);
  92                 if(verbose)fprintf(stderr,"front = %d, back = %d\n",front,back);
  93                 if(front<back)break;
  94                 if(front==back){
  95                         //comedi_poll(dev,subdevice);
  96                         usleep(10000);
  97                         continue;
  98                 }
  99
 100                 for(i=back;i<front;i+=sizeof(sampl_t)){
 101                         static int col = 0;
 102                         printf("%d ",*(sampl_t *)(map+(i%size)));
 103                         col++;
 104                         if(col==n_chan){
 105                                 printf("\n");
 106                                 col=0;
 107                         }
 108                 }
 109
 110                 ret = comedi_mark_buffer_read(dev,subdevice,front-back);
 111                 if(ret<0){
 112                         comedi_perror("comedi_mark_buffer_read");
 113                         break;
 114                 }
 115                 back = front;
 116         }
 117
 118         return 0;
 119 }
 120
 121 int prepare_cmd_lib(comedi_t *dev,int subdevice,comedi_cmd *cmd)
 122 {
 123         int ret;
 124
 125         ret = comedi_get_cmd_generic_timed(dev,subdevice,cmd,1e9/freq);
 126         if(ret<0){
 127                 comedi_perror("comedi_get_cmd_generic_timed\n");
 128                 return ret;
 129         }
 130
 131         cmd->chanlist = chanlist;
 132         cmd->chanlist_len = n_chan;
 133         cmd->scan_end_arg = n_chan;
 134
 135         if(cmd->stop_src==TRIG_COUNT)cmd->stop_arg = n_scan;
 136
 137         return 0;
 138 }
 139
 140 int prepare_cmd(comedi_t *dev,int subdevice,comedi_cmd *cmd)
 141 {
 142         memset(cmd,0,sizeof(*cmd));
 143
 144         cmd->subdev = subdevice;
 145
 146         cmd->flags = 0;
 147
 148         cmd->start_src = TRIG_NOW;
 149         cmd->start_arg = 0;
 150
 151         cmd->scan_begin_src = TRIG_TIMER;
 152         cmd->scan_begin_arg = 1e9/freq;
 153
 154         cmd->convert_src = TRIG_TIMER;
 155         cmd->convert_arg = 1;
 156
 157         cmd->scan_end_src = TRIG_COUNT;
 158         cmd->scan_end_arg = n_chan;
 159
 160         cmd->stop_src = TRIG_NONE;
 161         cmd->stop_arg = 0;
 162
 163         cmd->chanlist = chanlist;
 164         cmd->chanlist_len = n_chan;
 165
 166         return 0;
 167 }
 168
 169
 170