added link to firmware branch

Author: Jerzeek

1209/C1C1/index.md

@@ -6,4 +6,5 @@ license: CERN OHL S 2.0
 site: https://id-studiolab.github.io/Connected-Interaction-Kit/test/components/pico-expander/pico-expander
 source: https://github.com/id-studiolab/PicoExpander
 ---
-The PicoExpander is an expanderboard for the Raspberry Pi Pico series, it is developed by industrial design researchers from the Technical University of Delft. it enables our students to easily learn about electronics, programming and circuitpython.
+The PicoExpander is an expanderboard for the Raspberry Pi Pico series, it is developed by industrial design researchers from the Technical University of Delft. it enables our students to easily learn about electronics, programming and circuitpython.
+software: https://circuitpython.org/board/studiolab_picoexpander/