2 layers68 × 40 mm
Stm32-io extend
hardenedlinux/cheap-pcb
Cheap PCB: Better understanding the current status of hardware supply chain
44 parts170CC0-1.0
2 layers41 × 31 mm
A small custom PCB built around the STM32F103C8T6 (ARM Cortex-M3, 72 MHz) microcontroller.
- Size
- 41 × 31 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 32
- Nets
- 50
- Pads
- 132
- Tracks, vias
- 213, 26
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 13 Oct 2026
- Updated
- 13 Oct 2026
Overview
STM32 is an open-source printed circuit board by John-Coding-c, from the John-Coding-c/STM32F103C8T6-Board repository on GitHub, published under the MIT licence. It is a 2-layer board of 41 × 31 mm with 32 parts on 50 nets, routed with 213 tracks and 26 vias.
It is built around the STM32F103C8T6 and AMS1117-3.3. Its parts include 13 capacitors, 5 resistors, 4 connectors, 2 ICs and 1 diode. It belongs with the STM32 boards of this library.
Main components
2
STM32F103C8T6
LQFP-48(7x7)-40℃~+85℃ 12bit 20KB 2V~3.6V 32 Bit 37 64KB 72MHz ARM Cortex-M3 Built-in FLASH LQFP-48(7x7) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
AMS1117-3.3
SOT-223-40℃~+125℃ 0.003%Vout 1 1.1V@(800mA) 15V 1A 3.3V 5mA 72dB@(120Hz) Fixed Over Current Protection、Short Circuit Protection、Thermal shutdown Positive SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSAdvanced Monolithic SystemsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
README.mdSTM32F103C8T6 "Blue Pill"
A small custom PCB built around the STM32F103C8T6 (ARM Cortex-M3, 72 MHz) microcontroller.
Features
- MCU: STM32F103C8T6 (LQFP-48, 64 KB Flash, 20 KB RAM)
- Power: USB 5 V input → AMS1117-3.3 LDO → 3.3 V rail, with a power LED (D1)
- Clock: 16 MHz crystal (Y1) with load capacitors
- USB: USB Micro-B connector (J4) with 1.5 kΩ pull-up on D+
- Boot: SPDT switch (SW1) to select boot mode via BOOT0, with a 10 kΩ resistor (R4) on BOOT0
- Debug: 4-pin SWD header (SWDIO, SWCLK, 3.3 V, GND)
- Serial: 4-pin USART1 header (TX/RX, 3.3 V, GND)
- I2C: 4-pin I2C2 header (SCL/SDA with 1.5 kΩ pull-ups, 3.3 V, GND)
- Mounting: 4 × M3 mounting holes
Pin / Header Summary
| Header | Pins | Signals | MCU Pins |
|---|---|---|---|
| J1 (UART) | 4 | 3.3 V, TX, RX, GND | USART1 TX/RX (PA9 / PA10) |
| J2 (I2C) | 4 | 3.3 V, SCL, SDA, GND | I2C2 SCL / SDA (PB10 / PB11) |
| J3 (SWD) | 4 | 3.3 V, SWDIO, SWCLK, GND | PA13 / PA14 |
| J4 | — | USB Micro-B | PA11 (D-), PA12 (D+) |
| SW1 | — | BOOT0 select | BOOT0 |
Pin assignments are taken from the schematic net labels. Double-check against the schematic before wiring.
Specifications
| Item | Value |
|---|---|
| MCU | STM32F103C8T6 (LQFP-48, 7 × 7 mm) |
| Supply input | 5 V via USB |
| Regulator | AMS1117-3.3 (SOT-223) |
| Crystal | 16 MHz |
| Board title | STM32 Demo PCB, rev 0.1 (2025-08-01) |
| EDA tool | KiCad (project files .kicad_pro / .kicad_sch / .kicad_pcb) |
Bill of Materials
Full list: manufacture/STM32-BOM.csv
| Ref | Qty | Value | Footprint |
|---|---|---|---|
| C1, C2 | 2 | 22 µF | 0805 |
| C3 | 1 | 10 µF | 0603 |
| C4, C6, C7, C9, C10 | 5 | 100 nF | 0402 |
| C5, C8 | 2 | 10 pF | 0402 |
| C11 | 1 | 10 nF | 0402 |
| C12, C13 | 2 | 1 µF | 0402 |
| D1 | 1 | Red LED | 0603 |
| FB1 | 1 | 120 Ω ferrite bead | 0603 |
| J1, J2, J3 | 3 | 1×4 male pin header (2.54 mm) | — |
| J4 | 1 | USB Micro-B (Würth 629105150521) | — |
| R1, R2, R3, R5 | 4 | 1.5 kΩ | 0402 |
| R4 | 1 | 10 kΩ | 0402 |
| SW1 | 1 | SPDT slide switch | PCM12 |
| U1 | 1 | AMS1117-3.3 | SOT-223 |
| U2 | 1 | STM32F103C8T6 | LQFP-48 |
| Y1 | 1 | 16 MHz crystal | 3225 (4-pin) |
Manufacturing Files
The manufacture/ folder contains everything needed to order the board:
- Gerber files (
*.gbr): copper, solder mask, paste, silkscreen, and edge cuts - Drill file (
STM32.drl) - Pick-and-place (
STM32-all-pos.csv) - BOM (
STM32-BOM.csv)
Project Structure
STM32F103C8T6/
├── STM32.kicad_pro # KiCad project
├── STM32.kicad_sch # Schematic
├── STM32.kicad_pcb # PCB layout
├── 629105150521 (rev1).stp # Würth USB Micro-B 3D model
├── images/ # Schematic and 3D render images
└── manufacture/ # Gerbers, drill, BOM, pick-and-placeLicense
This project is licensed under the MIT License. See LICENSE for details.
The bundled Würth Elektronik 3D model is not covered by this license and remains under its owner's terms.
Parts
32| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 100n | Capacitor_SMD:C_0402_1005Metric | C4, C6, C7, C9, C10 |
| 4 | 1k5 | Resistor_SMD:R_0402_1005Metric | R1, R2, R3, R5 |
| 4 | MountingHole | MountingHole:MountingHole_2.1mm | H1, H2, H3, H4 |
| 3 | Conn_01x04_Male | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J1, J2, J3 |
| 2 | 10p | Capacitor_SMD:C_0402_1005Metric | C5, C8 |
| 2 | 1u | Capacitor_SMD:C_0402_1005Metric | C12, C13 |
| 2 | 22u | Capacitor_SMD:C_0805_2012Metric | C1, C2 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R4 |
| 1 | 10n | Capacitor_SMD:C_0402_1005Metric | C11 |
| 1 | 10u | Capacitor_SMD:C_0603_1608Metric | C3 |
| 1 | 120R | Inductor_SMD:L_0603_1608Metric | FB1 |
| 1 | 16MHz | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | AMS1117-3.3 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U1 |
| 1 | RED | LED_SMD:LED_0603_1608Metric | D1 |
| 1 | STM32F103C8T6 | Package_QFP:LQFP-48_7x7mm_P0.5mm | U2 |
| 1 | SW_SPDT | Button_Switch_SMD:SW_SPDT_PCM12 | SW1 |
| 1 | USB_B_Micro | Connector_USB:USB_Micro-B_Wuerth_629105150521 | J4 |
Questions
How big is the STM32 PCB?
It measures 41 × 31 mm and has 2 copper layers, 1.6 mm thick.
What parts does the STM32 use?
32 parts, built around the STM32F103C8T6 and AMS1117-3.3. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the STM32 KiCad files?
From the John-Coding-c/STM32F103C8T6-Board repository on GitHub, at the commit this page was made from: the board is STM32.kicad_pcb and its schematic STM32.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the STM32 design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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