This project was extracted from another, complex device project which originally targeted cheap STM32F103C8T6 board known as "bluepill" as main board. However, it soon became apparent that bluepill has shortcomings with USB interface, which was meant to be primary communication channel.
tl;dr bluepill cannot work with USB while being externally powered. It is designed to be powered with USB host only. Some bluepill boards have hardware bugs.
To overcome problems this board was designed. It has a number of enhancements and was thought to be maximally generic.
Enhancements:
- Improved USB
USB now has optional ESD protection, implements VBUS sense with software and is fully detachable via jumpers.
- Every pin has external connection
NOTE: some pins like PC14, PC15, BOOT0 don't have terminals at the board sides, but still have them at crystal mount points and boot pin headers.
- Separate analog terminals VDDA and GNDA and separate analog ground
NOTE: It is required to provide VDDA and GNDA or simply join them with VDD and GNDD. GNDA and GNDD may be joined on board with jumper. VDD and VDDA may be joined via terminals.
- Detachable add-ons
On-board LEDs and keys can be detached with jumpers.
- VDD and +5V inputs are protected power inputs.
All power supply nets are now protected with Schottky diodes.
The goal of this project is to learn electronics while creating a useful device, for everyone. So keep in mind that this device isn't designed by professional.
It is assumed that user is able to perform all necessary tasks related to device creation, which are not covered with project files. User must also perform all necessary precautions on every such task. See LICENSE.
This means things like electrical safety, soldering, parts ordering and PCB manufacturing are out of the scope. As a note, if you think you can buy bluepill, disassemble it and apply its parts to this board, then you're right. Bluepill has core parts, but some other uncommon ones need to be ordered.
Install Kicad EDA and open project file: device/df-pill/df-pill.pro.
Original project was made with Kicad EDA 5.1.5-3
You don't need any library installed, because project is fully autonomous.
It has all symbols, footprints and 3D models in device/df-pill/lib dir.
If you like to change anything it is recommended to first add new items to library and then use them in project to maintain autonomous project structure.
If you'd like to have multiple boards on a single copper plate
read device/panelization.md.
Schematic and and PCB have different, but related version formats.
- Schematic: X.Y
- PCB: X.Y.Z
Where X = major version, Y = minor version, Z = patch.
Schematic major version increment breaks external interface. Minor version increment changes components, but external interface is the same. Any schematic version change breaks PCB layout.
PCB's major and minor versions are from schematic versions. Patches are PCB modifications/optimizations that are fully compatible with current schematic.
A number of resources was used in this project. See reference.md for list.
This project is licensed under The Unlicense.
It contains library files from KiCAD EDA library in device/lib.
These files are licensed under KiCAD EDA Libraries License