Serial Wire Debug
PA13 is SWDIO and PA14 is SWCLK. The 3.3 V board rail is a reference for a compatible probe.
BluePill F4 pinout
The prototype schematic fits STM32F405RGT6 and uses separate 3.3 V digital and analog regulators. Confirm the PCB revision before applying these header numbers.
BluepillF405 prototype
54 contacts Current packageBluepillF405 prototype pinout
Header · J5
Header · J6
SWD header · J1
USB connector · J2
Boot header · J3
J5-16 · PA0
Routes to MCU PA0. Choose the applicable GPIO or peripheral function in the MCU documentation.
All 54 pins
| Pin | Signal | Direction | Function |
|---|---|---|---|
| J5-1 | GND Return | Return | Connects to the board’s ground plane. |
| J5-2 | GND Return | Return | Connects to the board’s ground plane. |
| J5-3 | VCC3V3 Power | Power | Connects to 3V3. Use the specified board power connection. |
| J5-4 | RESET Active-low reset | Active-low reset | Connects to MCU NRST. Use a compatible open-drain reset signal. |
| J5-5 | PB11 Configurable I/O | Configurable I/O | Routes to MCU PB11. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-6 | PB10 Configurable I/O | Configurable I/O | Routes to MCU PB10. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-7 | PB1 Configurable I/O | Configurable I/O | Routes to MCU PB1. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-8 | PB0 Configurable I/O | Configurable I/O | Routes to MCU PB0. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-9 | PA7 Configurable I/O | Configurable I/O | Routes to MCU PA7. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-10 | PA6 Configurable I/O | Configurable I/O | Routes to MCU PA6. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-11 | PA5 Configurable I/O | Configurable I/O | Routes to MCU PA5. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-12 | PA4 Configurable I/O | Configurable I/O | Routes to MCU PA4. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-13 | PA3 Configurable I/O | Configurable I/O | Routes to MCU PA3. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-14 | PA2 Configurable I/O | Configurable I/O | Routes to MCU PA2. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-15 | PA1 Configurable I/O | Configurable I/O | Routes to MCU PA1. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-16 | PA0 Configurable I/O | Configurable I/O | Routes to MCU PA0. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-17 | PC15 Configurable I/O | Configurable I/O | Routes to MCU PC15. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-18 | PC14 Configurable I/O | Configurable I/O | Routes to MCU PC14. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-19 | PC13 Configurable I/O | Configurable I/O | Routes to MCU PC13. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J5-20 | VBAT Power | Power | Connects to VBAT. Use the specified board power connection. |
| J6-1 | VCC3V3A Power | Power | Connects to Analog regulator output. Use the specified board power connection. |
| J6-2 | GNDA Return | Return | Connects to the board’s ground plane. |
| J6-3 | +5V Power | Power | Connects to 5V. Use the specified board power connection. |
| J6-4 | PB9 Configurable I/O | Configurable I/O | Routes to MCU PB9. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-5 | PB8 Configurable I/O | Configurable I/O | Routes to MCU PB8. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-6 | PB7 Configurable I/O | Configurable I/O | Routes to MCU PB7. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-7 | PB6 Configurable I/O | Configurable I/O | Routes to MCU PB6. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-8 | PB5 Configurable I/O | Configurable I/O | Routes to MCU PB5. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-9 | PB4 Configurable I/O | Configurable I/O | Routes to MCU PB4. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-10 | PB3 Configurable I/O | Configurable I/O | Routes to MCU PB3. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-11 | PA15 Configurable I/O | Configurable I/O | Routes to MCU PA15. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-12 | PA12 Configurable I/O | Configurable I/O | Routes to MCU PA12. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-13 | PA11 Configurable I/O | Configurable I/O | Routes to MCU PA11. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-14 | PA10 Configurable I/O | Configurable I/O | Routes to MCU PA10. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-15 | PA9 Configurable I/O | Configurable I/O | Routes to MCU PA9. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-16 | PA8 Configurable I/O | Configurable I/O | Routes to MCU PA8. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-17 | PB15 Configurable I/O | Configurable I/O | Routes to MCU PB15. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-18 | PB14 Configurable I/O | Configurable I/O | Routes to MCU PB14. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-19 | PB13 Configurable I/O | Configurable I/O | Routes to MCU PB13. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J6-20 | PB12 Configurable I/O | Configurable I/O | Routes to MCU PB12. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J1-1 | GND Return | Return | Connects to the board’s ground plane. |
| J1-2 | SWCLK Configurable I/O | Configurable I/O | Routes to MCU PA14. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| J1-3 | SWDIO Debug | Debug | Connects to MCU PA13 on the debug interface. |
| J1-4 | VCC3V3 Power | Power | Connects to 3V3. Use the specified board power connection. |
| J2-1 | VBUS Power | Power | Connects to VBUS. Use the specified board power connection. |
| J2-2 | D- Bidirectional | Bidirectional | USB data line. PCB net destination is PA11 through 22 Ω. |
| J2-3 | D+ Bidirectional | Bidirectional | USB data line. PCB net destination is PA12 through 22 Ω. |
| J2-4 | ID Circuit dependent | Circuit dependent | PCB net destination is PA10 through 1 kΩ. Check the connected circuit before driving the contact. |
| J2-5 | GND Return | Return | Connects to the board’s ground plane. |
| J2-6 | Shield Return | Return | Connects to the board’s ground plane. |
| J3-1 | 3V3 Power | Power | Connects to 3V3. Use the specified board power connection. |
| J3-2 | 3V3 Power | Power | Connects to 3V3. Use the specified board power connection. |
| J3-3 | BOOT0 Circuit dependent | Circuit dependent | PCB net destination is BOOT0 with 100 kΩ pull-down. Check the connected circuit before driving the contact. |
| J3-4 | BOOT1 Circuit dependent | Circuit dependent | PCB net destination is BOOT1 with 100 kΩ pull-down. Check the connected circuit before driving the contact. |
Signal assignments
USART1 on PA9/PA10
PA9 is TX and PA10 is RX in the default USART1 mapping. Select the matching firmware configuration.
Electrical limits
| Parameter | Limit | Conditions and source |
|---|---|---|
| Board logic rail3.3 V nominal | 3.3 V nominal | Check the fitted regulator and MCU datasheet before attaching an external circuit. USB is the only supply used in the example. BluepillF405 prototype connector map |
| External high-speed oscillator8 MHz | 8 MHz | Use the correct HSE frequency in firmware clock calculations. BluepillF405 prototype connector map |
Models and documents
The maps follow the listed PCB variants. Match the board markings and connector positions to the referenced schematic before applying power.
- BluepillF405 prototype
- The prototype schematic fits STM32F405RGT6 and uses separate 3.3 V digital and analog regulators. Confirm the PCB revision before applying these header numbers.
- STMicroelectronics MCU datasheet· MCU electrical specifications and package pin functions.
- BluepillF405 prototype schematic· PCB power, debug, connector and peripheral wiring.
- Original BluePill F4 development thread· Prototype revisions and the reported reset-switch wiring issue.