stm32f072 dev board with arduino nano alike pinout

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OtterPill is a 3$ STM32F072 devboard featuring USB 2.0 full-speed, a DFU Bootloader, a USB-PD Phy and Arduino nano alike pinout and size.

Changelog V1.2: BOM cost reduction by ~40%, PCB can be fully populated by JLCSMT, more efficient buck converter (PCB gets less warm at 20V), GND-hook for probing, Reset-Pin exposed as pad, power pads for 20V/5A

How do I get an OtterPill?

Via tindie (if sold out DM via Twitter, I might have a few left ;))

Or you can generate a basic firmware, with HAL init and Makefile, with CubeMX. The binary can then be build with make and flashed with dfu-utils. To enter DFU mode, press and hold the Button while plugging in power.

$ make"\n"$ dfu-util -a 0 -s 0x08000000:leave -D build/firmware.bin"\n"

You can build and flash the firmware via Arduino as described here. Thank you ansemjo :3

Thank you @jamesmunns! :3

HW v1.2/OtterPill.pdf

Pinout by SarahhhhFoster :)


This is a working USB-PD example using ChibiOS, a new voltage can be requested by pressing the Button.

Most Arduino shields should be compatible.


  • Replace U1 with ESDU5V0H4
  • Add a TVS Diode to VBUS (e.g. SJD12A22L01) -> Added series resistor to reduce ringing
  • Remove R8, R9
  • Redraw the FUSB302B Symbol -> forgot why, works great
  • Consider switching to STUSB4500 (Easier PD requesting, same price) -> FUSB works great, no need to change
  • Add VBUS ADC

@jamesmunns for creating the Rust examples.

@MayaPosch for creating the Nodate framework and adding the OtterPill.

@ansemjo for creating a PlatformIO configuration.

@SarahhhhFoster for creating the awesome pinout diagram.