calibration.c

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#include "calibration.h"

// reset calibration
void reset_offsets(void) {
    int i;
    for (i = 0; i < NUM_CHANNELS; i++) {
        calibration.offsets[i] = 0;
    }
}

void reset_scales(void) {
    int i;
    for (i = 0; i < NUM_CHANNELS; i++) {
        calibration.scales[i] = 1;
    }
}

int read_calibration(struct rl_conf* conf) {

    // open calibration file
    FILE* file = fopen(CALIBRATION_FILE, "r");
    if (file == NULL) {
        // no calibration file available
        reset_offsets();
        reset_scales();
        status.calibration_time = 0;
        return FAILURE;
    }
    // read calibration
    fread(&calibration, sizeof(struct rl_calibration), 1, file);

    // reset calibration, if ignored
    if (conf->calibration == CAL_IGNORE) {
        reset_offsets();
        reset_scales();
    }

    // store timestamp to conf and status
    status.calibration_time = calibration.time;

    // calculate values for high rates
    if (conf->sample_rate == 32000 || conf->sample_rate == 64000) {
        int i;
        for (i = 0; i < NUM_CHANNELS; i++) {
            calibration.offsets[i] = calibration.offsets[i] / 256;
            calibration.scales[i] = calibration.scales[i] * 256;
        }
    }

    // close file
    fclose(file);

    return SUCCESS;
}