How to configure LEDs (P-ROC/P3-ROC)

Related Config File Sections

This guide explains how to configure MPF to use LEDs attached to a Multimorphic PD-LED board with either a P-ROC or P3-ROC.

Note that if you’re using a P-ROC/P3-ROC and you want to use serial-controlled LEDs (NeoPixels, etc.), then you can do that with a P-ROC/P3-ROC by using a FadeCandy instead of a PD-LED. You can also mix-and-match PD-LEDs and FadeCandy LEDs.

Understanding the PD-LED board

The PD-LED controls up to 84 individual LED elements, which can be used to control individual single color LEDs, or (more likely), combined into groups to control RGB LEDs.

The PD-LED uses a “direct” connection method for LEDs, where each LED has connections for each color element running back to the PD-LED. This is a different architecture than the serial-controlled “Neo Pixel” type LEDs that other hardware uses.

LED number:

Since the PD-LED board directly drives single color LED outputs, when you use it with RGB LEDs, you combine three outputs into a single RGB LED. The PD-LED supports both common cathode (common ground) and common anode (common 3.3v) LEDs, so each LED you buy has four pins (red, green, blue, and common). When you configure the hardware number for a PD-LED RGB LED, you specify four parts, separated by dashes:

  1. The address of the PD-LED board on the serial chain (as configured via the DIP switches on the PD-LED.
  2. The output number of the red element.
  3. The output number of the green element.
  4. The output number of the blue element.

You separate those with dashes, so an example PD-LED configuration might look like this:

      number: 8-0-1-2

The example above configures “l_led0” as the LED connected to PD-LED board at address 8, using outputs 0, 1, and 2 as its red, green, and blue connections.


The PD-LED allows you to use either common anode or common cathode LEDs. (See the PD-LED documentation for details. The type of LED would dictate whether you hook it up between the PD-LED’s output and ground, or between the output and 3.3v.) You can then use the config file to specify which type of LED you have, such as:

      number: 8-60-61-62
         polarity: True

True = common cathode (or common ground), False = common anode (or common 3.3V)

Note that DIP Switch 6 on the PD-LED board controls whether the “default” state of the LEDs after a reset is high or low. Basically it’s whether all the LEDs turn on or turn off when the board is reset. Which position does what is dependent on whether you’re controlling the anode or the cathode with your outputs, so basically if you turn on your PD-LED and all your LEDs turn on, then flip DIP switch 6 on the PD-LED to the opposite position and power cycle the board.