STM32 Serial Flasher
STM32 Serial Flasher is a VS Code extension for programming STM32 microcontrollers with .hex and .bin firmware through the chip's built-in ROM USART bootloader.
Paired with a USB-UART bridge and an auto-reset circuit, a single USB-C cable handles the entire workflow directly inside VS Code: bootloader entry, chip erase, programming, verification, and reset-to-run. No ST-Link or external flashing utility is required.
简体中文 · Usage Reference · Hardware Notes · Contributing
Features
- Multiple Interfaces: Interactive Webview panel, Activity Bar sidebar, Command Palette, editor context menus, and status bar integration.
- Automatic Firmware Discovery: Scans workspace build folders, filters out compiler probe artifacts (such as
CMakeFiles), and parses Intel HEX base addresses or raw binaries.
- Hardware Reset Modes: Built-in presets for CH340C and CH340X auto-download circuits, manual bootloader entry, and configurable DTR/RTS pin mappings.
- State Persistence & Profiles: Remembers last-used serial settings; supports named project profiles for different boards and build targets.
- VS Code Tasks Integration: Contributes a task provider to chain build and flash steps into a single automated workflow.
- Diagnostics & Output Logs: Integrated diagnostics for serial enumeration and extension host status, complete with detailed operation logs.
Installation
Install STM32 Serial Flasher from the VS Code Marketplace, or via terminal:
code --install-extension totok22.serialflash-stm32
[!NOTE]
The published Marketplace release is 0.2.1. The bilingual panel and expanded documentation are documented in CHANGELOG.md. For local builds and debugging, see CONTRIBUTING.en.md.
Panel Preview
The panel language adapts automatically to the VS Code display language (English and Chinese supported).
Quick Start
- Build Firmware: Open your firmware project in VS Code and build your
.hex or .bin binary.
- Connect Device: Plug your board into the computer and ensure no other terminal or monitor is holding the serial port.
- Open Panel: Click the SerialFlash icon in the Activity Bar or run
SerialFlash: Open Flasher Panel.
- Configure: Select the serial port, firmware file, and reset mode matching your circuit.
- Flash: Click Flash or press
Cmd+Alt+F (macOS) / Ctrl+Alt+F (Windows/Linux).
- Inspect Log: Check the Output channel for bootloader version, PID, erase, write, and verification status.
Wiring & Reset Modes
Ensure the MCU breaks out the USART pins supported by its system ROM bootloader (refer to ST AN2606). Connect USB-UART TX to MCU RX, RX to MCU TX, and share a common ground.
| Reset Mode |
Description |
dtr-low-rts-high |
CH340C classic circuit (transistor-based BOOT0/RESET control; default) |
ch340x |
CH340X direct circuit (using RTS# and enhanced DTR control lines) |
none |
Manual mode (toggle BOOT0 and reset buttons manually; DTR/RTS lines idle) |
dtr-high-rts-low |
Generic reversed preset (DTR high asserts reset, RTS low sets boot) |
custom |
Custom mode (manually configure DTR/RTS assert/deassert states) |
For complete schematics, logic levels, and reset timing, see Hardware Notes.
Firmware & Flash Addresses
- Selection Priority: If a configured firmware path (or previously remembered path) exists, it takes precedence. Otherwise, when
autoDiscoverFirmware is enabled, the workspace is scanned for candidates.
- Default Flash Address:
| Format |
Default Address |
Note |
Intel HEX (.hex) |
Base address in file |
Parsed from the extended linear address record |
Raw Binary (.bin) |
0x08000000 |
Default STM32 internal flash start address |
An explicit serialFlash.flashAddress setting overrides both defaults. For all configuration options, see the Usage Reference.
Runtime Environments
- Supported Hosts: VS Code Desktop 1.90+ on macOS, Windows, and Linux.
- Port Visibility: Serial communication runs in the extension host. In Remote SSH, WSL, or Dev Containers, serial ports belong to the machine hosting the extension. Run
SerialFlash: Run Diagnostics to inspect the environment.
- Unsupported: Browser-based editors (
vscode.dev, github.dev) lack native serial access and cannot run flashing workflows.
Documentation Index
- Usage Reference: Complete command list, configuration options, named profiles, tasks, and troubleshooting.
- Hardware Notes: CH340C/CH340X schematics, control polarity conventions, and reset timing.
- Protocol Reference: STM32 USART ISP bootloader packet format and supported commands.
- Hardware Validation: Physical hardware test criteria and report template.
- Contributing: Setting up local development, F5 debugging, and VSIX packaging.
- Changelog: Release history and upcoming features.
License
MIT
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