This material has been superseded. Visit learn.bela.io for the maintained version.

Command-line arguments

Every Bela program supports a standard set of command-line arguments, listed below. Either the long form or the short (single-character) form can be used

Other arguments can be added in each project. With the exception of -p and -v, the standard arguments all use capital letters, leaving the lowercase letters free for user-defined arguments. The Bela_usage() function explains the standard arguments as follows:

   --period [-p] period:               Set the hardware period (buffer) size in audio samples
   --dac-level [-D] dBs:               Set the DAC output level (0dB max; -63.5dB min)
   --adc-level [-A] dBs:               Set the ADC input level (0dB max; -12dB min)
   --pga-gain-left dBs:                Set the Programmable Gain Amplifier for the left audio channel (0dBmin; 59.5dB max; default: 16dB)
   --pga-gain-right dBs:               Set the Programmable Gain Amplifier for the right audio channel (0dBmin; 59.5dB max; default: 16dB)
   --hp-level [-H] dBs:                Set the headphone output level (0dB max; -63.5dB min)
   --mute-speaker [-M] val:            Set whether to mute the speaker initially (default: no)
   --use-analog [-N] val:              Set whether to use ADC/DAC analog (default: yes)
   --use-digital [-G] val:             Set whether to use digital GPIO channels (default: yes)
   --analog-channels [-C] val:         Set the number of ADC/DAC channels (default: 8)
   --digital-channels [-B] val:        Set the number of GPIO channels (default: 16)
   --receive-port [-R] val:            Set the receive port (default: 9998)
   --transmit-port [-T] val:           Set the transmit port (default: 9999)
   --server-name [-S] val:             Set the destination server name (default: '127.0.0.1')
   --mux-channels [-X] val:            Set the number of channels to use on the multiplexer capelet (default: not used)
   --audio-expander-inputs [-Y] vals:  Set the analog inputs to use with audio expander (comma-separated list)
   --audio-expander-outputs [-Z] vals: Set the analog outputs to use with audio expander (comma-separated list)
   --pru-file val:                     Set an optional external file to use for the PRU binary code
   --pru-number val:                   Set the PRU to use for I/O (options: 0 or 1, default: 0)
   --disable-led                       Disable the blinking LED indicator
   --disable-cape-button-monitoring    Disable the monitoring of the Bela cape button (which otherwise stops the running program)
   --verbose [-v]:                     Enable verbose logging information
   --help [-h]:                        Print this menu