Documentation

Converts data arrays stored in channel format into DAC buffer format. The DAC buffer must be of length (number of channels) * (number of data points). The buffer should be initialized to zero before the first call. The data array represents a single channel. Since the DAC requires the data sample-by-sample rather than channel-by-channel, the typical conversion operration is performed as follows:

    for (k = 0; k < len; k++) {
       val = floor (dac_conversion_factor * data[k]);
       if (fabs(val) >= dac_max) {
          buf[k * number_of_channels + chnnum] = 
                            (val > 0) ? dac_max : -dac_max;
       }
       else {
          buf[k * number_of_channels + chnnum] = (short) val;
       }
    }
    

Returns:

0 if successful, <0 otherwise

Parameters:

buf - data buffer for an epoch
data - Channel data array
chnnum - DAC channel number
len - length of data buffer

Author:

CP, June 99

See Also:

DAC API, Arbitrary Waveform Generator