This OSH Park project is a starting point for a few different projects that will use the STM32 WLx5C series of sub-GHz RF Cortex-M4 processors.
The 48-pin Quad Flat Pack (-C) footprint comes in a few different versions with the same pin-out:
Designation | Features |
STM32WLE5C | ARM Cortex-M4. Includes LoRa modulation |
STM32WL55C | ARM Cortex-M4 and Cortex-M0+. LoRa |
STM32WL54C | ARM Cortex-M4 and Cortex-M0+. No LoRa |

It’s (very) small, to fit in small places, with 0.05″ headers. But it has all the pins broken out for anything I need to do. There is also a baseboard with more usual 0.1″ pitch connectors to help prototyping.

Fresh off my soldering iron, I haven’t actually powered it on yet! I’ve tested that power and ground aren’t shorted, but other than that… wish me luck!