This test page gives control over the BBB's pins. Select a pin that you wish to use from the relevant drop-down menu and click 'Go'.

A new widget will appear with controls relevant to that pin.

Make sure to check the error log to see if something goes wrong.

To see the pin out diagram of the BBB, click here.

To export/unexport a pin means to enable/disable it. Apart from the obvious use case, sometimes this can be required if you use two PWM channels that share the same frequency base.

You won't be able to change the frequency until you unexport one of them.

The frequency must be a decimal number greater than 0.

The duty cycle describes the proportion of off/on time per period. This number is specified as a ratio, with values ranging from 0 to 1.

The polarity determines if the duty represents the 'active high' or 'active low' portion. By default, the duty cycle represents the 'active high' portion.