Experiments towards a programmer for the Padauk 8-Bit MCUs based on a WCH CH32V003. The goal is to allow for a programmer with a BOM <$0.50, fitting for a $0.03 MCU. This initialial phase covers voltage generators and programming algorithms, integration with rv003usb is anticipated as a later step.
One of the more ambitious design choices is to use a boost converter built around discrete components and the microcontroller itself, used as switching signal generator and software feedback control. This allows reducing reliance on a booster ICs, which costs significantly more and is often not available. A common LM358 OPamp is used as a linear regulator to control supply voltages for the target device.
Hardware conceptualization, architecture and design was done manually using LTSpice and EasyEDA, based on Easy-PDK-Programmer lite
Bringup and documentation with agentic GenAI (Claude Code and Codex), using earlier experiements and the free-pkd Firmware as references. The Firmware is based on ch32fun
Design/- design notes and sims (LTspice.asc, sizing spreadsheet)Firmware/- firmware sources + build environment (ch32fun)Testboards/- hardware test boards (schematics/PCB docs)
Bring-up notes and captures (booster electrical characterization + PDK programming experiments) live in Design/README.md.
Firmware details and build notes live in Firmware/README.md.
- Hardware design in
Testboards/is released under CC-BY-SA-4.0. - Firmware under
Firmware/src_*is built on top ofFirmware/ch32fun(MIT).