OtterPill

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 will be exposed as pad, power pads for 20V/5A

More documentation and firmware examples will be aviable soon (including pinout diagram).

Building and Flashing

Via Arduino

You can build and flash the firmware via Arduino as described here.

Via Makefile and DFU

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

USB-PD example firmware

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

https://github.com/Jan--Henrik/USB-PD-Firmware

Images

Rev 1.1

Rev 1.2