/** * Start the the ADC sampling, unless the external trigger command * is set it will begin sampling as soon as the usbdux device has been * initialized. * The final three arguments are very important to get right * as the recorder thread will use them to determine where to write it's samples and * when it's reached end of the buffer. It doesn't care about the c_buffer class * at all. * @param arg_device name of the comedi device e.g., 'comedi0' * @param arg_sample_rate the rate the usb_dux should sample with in hertz (max=3[Mhz]}) * @param arg_start_address the start address of the circle buffer sample should be loading into * @param arg_end_address the end address of the cicle buffer. * @param arg_buffer_size byte size of the buffer. */ int start_Sampling(char* arg_device, uint32_t arg_sample_rate, char* arg_start_address, char* arg_end_address, int arg_buffer_size){ _channel_amount = 16; _sample_rate = arg_sample_rate; unsigned int chanlist[_channel_amount]; unsigned int convert_arg = 1e9 / _sample_rate; int ret; comedi_cmd *cmd = (comedi_cmd *) calloc(1, sizeof(comedi_cmd)); _device = comedi_open(arg_device); int buffer = 1048576*40; buffer = (buffer * 4096)/4096; if(comedi_set_max_buffer_size(_device, 0, buffer) < 0 ){ printf("Failed to set max buffer size to %i bytes\n", buffer); return -1; } else printf("Maximum buffer size set to %i bytes\n", comedi_get_max_buffer_size(_device,0)); if(comedi_set_buffer_size(_device, 0, buffer) < 0){ printf("Failed to set buffer size to %iBytes\n", buffer); return -1; } else printf("Buffer size set to %iBytes\n", comedi_get_buffer_size(_device,0)); if(!_device){ errx(1, "unable to open device"); comedi_perror("/dev/comedi0"); return -1; } for(int i = 0; i < _channel_amount; i++) chanlist[i] = i; comedi_set_global_oor_behavior(COMEDI_OOR_NUMBER); if((ret = comedi_get_cmd_generic_timed(_device, 0, cmd, _channel_amount,0)) < 0){ printf("comedi_get_cmd_generic_timed failed\n"); return ret; } cmd->chanlist = chanlist; cmd->stop_src = TRIG_NONE; cmd->stop_arg = 0; cmd->convert_arg = convert_arg; //setup the sampling to start from the trigger. //cmd->start_src = TRIG_EXT //cmd->start_arg = 1; /* call test twice because different things are tested? * if tests are successful run sampling command */ if((ret = comedi_command_test(_device, cmd)) != 0 || (ret = comedi_command_test(_device, cmd)) != 0 || (ret = comedi_command(_device, cmd)) < 0){ fprintf(stderr, "err: %d\n", ret); return -1; } FILE* dux_fp; if((dux_fp = fdopen(comedi_fileno(_device), "r")) <= 0) comedi_perror("fdopen"); char* write_address = arg_start_address; Utility::SNAP_SAMPLE = 0; Utility::LAST_SAMPLE = 0; uint64_t active_sample = 0; uint32_t tmp_block = 0; int samples_pr_block = 4096/sizeof(Type); while((ret = fread(write_address, 1, 4096,dux_fp)) >= 0){ write_address += 4096; tmp_block += 1; active_sample += samples_pr_block; Utility::LAST_SAMPLE += samples_pr_block; if(tmp_block >= Utility::SNAPSHOT_BLOCK_SIZE){ //printf("signalling serial snapshotter\n"); tmp_block = 0; Utility::SNAP_SAMPLE = active_sample; Utility::SNAP_READY = true; Utility::CV.notify_one(); } if(write_address == arg_end_address){ write_address -= arg_buffer_size; //printf("resetting to beginning of buffer\n"); } if(_stop == true) break; } if(ret < 0) perror("read"); comedi_cancel(_device, 0); return 0; }
int _comedi_get_buffer_size(comedi_t *it, unsigned int subdev) { return comedi_set_buffer_size(it, subdev, 0); }