Serial Wire Debug
PA13 is SWDIO and PA14 is SWCLK. The 3.3 V board rail is a reference for a compatible probe.
Black Pill pinout
This STM32F103 board uses a four-contact SWD connector with GND, CLK, DIO and 3V3 in that order. Its debug connector differs from the Blue Pill and WeAct MiniF4.
STM32F103C8T6 Black Pill 43 contacts
WeAct MiniF4 V3.1
44 contacts Current packageWeAct MiniF4 V3.1 pinout
Header 1
Header 2
SWD header
H2-5 · A8
Routes to MCU PA8. Choose the applicable GPIO or peripheral function in the MCU documentation.
All 44 pins
| Pin | Signal | Direction | Function |
|---|---|---|---|
| H1-1 | 5V Power | Power | Connects to 5V. Use the specified board power connection. |
| H1-2 | G Return | Return | Connects to the board’s ground plane. |
| H1-3 | 3.3 Power | Power | Connects to 3V3. Use the specified board power connection. |
| H1-4 | B10 Configurable I/O | Configurable I/O | Routes to MCU PB10. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-5 | B2 Configurable I/O | Configurable I/O | Routes to MCU PB2. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-6 | B1 Configurable I/O | Configurable I/O | Routes to MCU PB1. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-7 | B0 Configurable I/O | Configurable I/O | Routes to MCU PB0. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-8 | A7 Configurable I/O | Configurable I/O | Routes to MCU PA7. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-9 | A6 Configurable I/O | Configurable I/O | Routes to MCU PA6. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-10 | A5 Configurable I/O | Configurable I/O | Routes to MCU PA5. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-11 | A4 Configurable I/O | Configurable I/O | Routes to MCU PA4. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-12 | A3 Configurable I/O | Configurable I/O | Routes to MCU PA3. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-13 | A2 Configurable I/O | Configurable I/O | Routes to MCU PA2. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-14 | A1 Configurable I/O | Configurable I/O | Routes to MCU PA1. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-15 | A0 Configurable I/O | Configurable I/O | Routes to MCU PA0. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-16 | R Active-low reset | Active-low reset | Connects to MCU NRST. Use a compatible open-drain reset signal. |
| H1-17 | C15 Configurable I/O | Configurable I/O | Routes to MCU PC15. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-18 | C14 Configurable I/O | Configurable I/O | Routes to MCU PC14. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-19 | C13 Configurable I/O | Configurable I/O | Routes to MCU PC13. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H1-20 | VB Power | Power | Connects to VBAT. Use the specified board power connection. |
| H2-1 | B12 Configurable I/O | Configurable I/O | Routes to MCU PB12. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-2 | B13 Configurable I/O | Configurable I/O | Routes to MCU PB13. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-3 | B14 Configurable I/O | Configurable I/O | Routes to MCU PB14. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-4 | B15 Configurable I/O | Configurable I/O | Routes to MCU PB15. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-5 | A8 Configurable I/O | Configurable I/O | Routes to MCU PA8. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-6 | A9 Configurable I/O | Configurable I/O | Routes to MCU PA9. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-7 | A10 Configurable I/O | Configurable I/O | Routes to MCU PA10. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-8 | A11 Configurable I/O | Configurable I/O | Routes to MCU PA11. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-9 | A12 Configurable I/O | Configurable I/O | Routes to MCU PA12. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-10 | A15 Configurable I/O | Configurable I/O | Routes to MCU PA15. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-11 | B3 Configurable I/O | Configurable I/O | Routes to MCU PB3. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-12 | B4 Configurable I/O | Configurable I/O | Routes to MCU PB4. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-13 | B5 Configurable I/O | Configurable I/O | Routes to MCU PB5. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-14 | B6 Configurable I/O | Configurable I/O | Routes to MCU PB6. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-15 | B7 Configurable I/O | Configurable I/O | Routes to MCU PB7. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-16 | B8 Configurable I/O | Configurable I/O | Routes to MCU PB8. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-17 | B9 Configurable I/O | Configurable I/O | Routes to MCU PB9. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H2-18 | 5V Power | Power | Connects to 5V. Use the specified board power connection. |
| H2-19 | G Return | Return | Connects to the board’s ground plane. |
| H2-20 | 3.3 Power | Power | Connects to 3V3. Use the specified board power connection. |
| H3-1 | 3.3V Power | Power | Connects to 3V3. Use the specified board power connection. |
| H3-2 | SWDIO Debug | Debug | Connects to MCU PA13 on the debug interface. |
| H3-3 | SWCLK Configurable I/O | Configurable I/O | Routes to MCU PA14. Choose the applicable GPIO or peripheral function in the MCU documentation. |
| H3-4 | GND Return | Return | Connects to the board’s ground plane. |
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. WeAct MiniF4 V3.1 connector map |
| External high-speed oscillator25 MHz | 25 MHz | Use the correct HSE frequency in firmware clock calculations. WeAct MiniF4 V3.1 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.
- WeAct MiniF4 V3.1
- WeAct documents the same side-header and SWD pin definitions for V3.0 and V3.1. The map covers those headers on V3.1. See the WeAct schematic for USB-C and the optional flash device.
- STM32-base · WeAct MiniF4 V3.1· Board identification, connector numbering and documented net destinations.
- STMicroelectronics MCU datasheet· MCU electrical specifications and package pin functions.
- WeAct MiniF4 V3.1 schematic· PCB power, debug, connector and peripheral wiring.
- WeAct MiniF4 hardware revisions· Revision changes, including regulator and USB-C power routing.