Blue Pill and STM32 H103 in PICSimLab: The Only Two STM32 Boards
Let us start with the fact that matters most, because many pages get it wrong: PICSimLab supports exactly two STM32 microcontrollers — the STM32F103C8T6 on the Blue Pill board and the STM32F103RBT6 on the STM32 H103 board. There are no other STM32 boards, no other STM32 families, and no Nucleo or Discovery boards in PICSimLab. This page documents those two boards exactly as they are.
Overview
Both boards run on the qemu-stm32 backend — a PICSimLab-adapted QEMU build with an STM32 implementation. The boards themselves are deliberately minimal. The official description of the Blue Pill is a “generic board only with reset, serial and crystal circuits”, and the STM32 H103 is a “generic board only with reset, one push button, serial and crystal circuits”. They are simple carriers for the chip, not full replicas of feature-rich development boards.
Supported MCUs
| Board | Microcontroller | Board circuits (official description) | Backend |
|---|---|---|---|
| Blue Pill | STM32F103C8T6 | Reset, serial and crystal only | qemu-stm32 |
| STM32 H103 | STM32F103RBT6 | Reset, one push button, serial and crystal | qemu-stm32 |
Backend & debugging
Debugging is remote arm-gdb: enable debugging in PICSimLab’s configuration window, then connect arm-none-eabi-gdb (or gdb-multiarch) to the simulator with target extended-remote localhost:1234. The official documentation also shows how to configure STM32CubeIDE to connect for debugging, and a PlatformIO/VSCode setup using picsimlab_tool to upload firmware with a custom debug tool. For STM32 boards the Code Project Wizard generates VSCode + PlatformIO projects; the official templates cover both boards with the Arduino framework and with CMSIS.
What you can do
- Build, run and breakpoint-debug F103 firmware (Arduino-framework or CMSIS templates) without a physical Blue Pill or ST-Link.
- Exercise serial-based designs, using the virtual serial port setup on the desktop version.
- Attach spare parts to the pins and watch signals on the two-channel oscilloscope while the QEMU core runs your binary.
Real limits
- Only two F103 chips — full stop. There is no STM32F4, F7, H7 or L-series support and no other STM32 board in the official documentation or template list. Claims of “STM32 family simulation” go beyond what PICSimLab offers.
- The boards are simple/generic: reset, serial and crystal circuits (plus one push button on the H103). They are not pin- and peripheral-complete replicas of the retail boards.
- The official qemu-stm32 documentation is brief and publishes no peripheral coverage list or performance promises — peripheral behaviour is whatever the adapted QEMU implements, so verify the specific peripherals your project needs.
- PICSimLab has no source editor; code is written in VSCode + PlatformIO or STM32CubeIDE, as with real hardware.
Install PICSimLab from the download page, choose Blue Pill or STM32 H103, and keep expectations set to “two F103 chips, honestly simulated” — within that scope, it is genuinely useful.