M control.  The
   shift registers and GPIO extenders only provide simple on/off controls, so
   they're not as flexible, but they're fine for devices that don't need
   intensity controls.
</p>
<p>
   You can set up any combination of output device types.  For each such chip
   you attach to the Pico, you have to add an entry to the JSON configuration
   to tell the software about the chip.  See the reference sections linked
   above for details on how to do that for each type of chip.
</p>

<h4>Booster ci