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 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 ;))
Building, Flashing and Frameworks
Via Makefile and DFU (C, C++)
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
Via Arduino
You can build and flash the firmware via Arduino as described here.
Via PlatformIO
https://gist.github.com/ansemjo/ab1c12f7c78abb140f7272501aff2a55 Thank you ansemjo :3
Via Nodate (野点) (C++, Ada)
https://github.com/MayaPosch/Nodate
Rust
Thank you @jamesmunns! :3
https://github.com/jamesmunns/OtterPill-rs
Schematic
Pinout
Pinout by SarahhhhFoster :)
Examples and projects
Blink example firmware
STM workshop based on OtterPill
https://github.com/Jana-Marie/hackerhotel-stm-workshop
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/Jana-Marie/USB-PD-Firmware
IBM dials retrofit
https://github.com/Jana-Marie/IBM-dials-retrofit
Shields and addons
Most Arduino shields should be compatible.
USB-to-CAN-adapter
Todo for HW v1.3
- 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
Special thanks
@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.
Images
Rev 1.2
License
Copyright Jana Marie Hemsing 2022.
This source describes Open Hardware and is licensed under the CERN-OHL-S v2.
You may redistribute and modify this source and make products using it under the terms of the CERN-OHL-S v2 (https://ohwr.org/cern_ohl_s_v2.txt).
This source is distributed WITHOUT ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING OF MERCHANTABILITY, SATISFACTORY QUALITY AND FITNESS FOR A PARTICULAR PURPOSE. Please see the CERN-OHL-S v2 for applicable conditions.
Source location: https://github.com/Jana-Marie/electrostatic-adhesion-plate
As per CERN-OHL-S v2 section 4, should You produce hardware based on this source, You must where practicable maintain the Source Location visible on the external case of the Gizmo or other products you make using this source.