# Blue Pill STM32F103C8T6

> Popular low-cost development board based on the STM32F103C8T6 ARM Cortex-M3 microcontroller running at 72 MHz. Features 64 KB flash, 20 KB SRAM, and extensive peripheral support for embedded development.

## Quick Facts

- **Brand:** Generic
- **Board Type:** dev-board
- **Price:** ~$2.5
- **Product Readiness:** developer
- **CPU:** STM32F103C8T6
- **CPU Architecture:** ARM Cortex-M3
- **CPU Cores:** 1
- **RAM:** 20 KB
- **Flash:** 64 KB
- **USB:** Micro-B
- **Power:** 5V
- **Operating Voltage:** 3.3V

## Open Source

- **Firmware:** Yes
- **Schematics:** Yes
- **PCB Layout:** No

## Compatible Firmware

arduino, STM32CubeIDE, PlatformIO, micropython, Rust, Zephyr RTOS

## Use Cases

- Embedded Systems
- Prototyping
- Motor Control
- Industrial IoT
- Education
- Robotics

## Components

- **STM32F103C8T6** (Processor): STMicroelectronics 32-bit ARM Cortex-M3 MCU running at 72 MHz with 64 KB flash, 20 KB SRAM, and rich peripheral set including CAN, USB, and multiple timers. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fresource%2Fen%2Fdatasheet%2Fstm32f103c8.pdf&ref=openhardware.directory&product=blue-pill-stm32&source=md-export)
- **8 MHz Crystal** (Crystal): External 8 MHz crystal oscillator providing the main clock source, multiplied by PLL to achieve the 72 MHz system clock. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fresource%2Fen%2Fdatasheet%2Fstm32f103c8.pdf&ref=openhardware.directory&product=blue-pill-stm32&source=md-export)
- **32.768 kHz Crystal** (Crystal): Low-speed external crystal for the real-time clock (RTC) peripheral, enabling accurate timekeeping in low-power modes. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fresource%2Fen%2Fdatasheet%2Fstm32f103c8.pdf&ref=openhardware.directory&product=blue-pill-stm32&source=md-export)

## Protocols

- **SPI**
- **I2C**
- **UART**
- **CAN**
- **PWM**
- **ADC**
- **SWD**
- **USB**

## Description

# Blue Pill STM32F103C8T6

The Blue Pill is one of the most widely used low-cost STM32 development boards in the embedded community. Based on the STM32F103C8T6 ARM Cortex-M3 microcontroller, it offers significantly more processing power and peripherals than 8-bit Arduino boards at a fraction of the cost.

## Key Features

- **STM32F103C8T6** ARM Cortex-M3 at **72 MHz**
- **64 KB flash** (many chips actually have 128 KB accessible)
- **20 KB SRAM**
- **37 GPIO pins** (most 5V tolerant)
- 2x SPI, 2x I2C, 3x UART, 1x CAN, 1x USB 2.0 Full Speed
- 2x 12-bit ADC (10 channels)
- 7x timers (including advanced motor control timer)
- SWD debug interface (via ST-Link)
- 8 MHz and 32.768 kHz crystals onboard
- Micro-USB connector

## Programming Support

- **STM32CubeIDE** — ST's official IDE with HAL and LL drivers
- **Arduino IDE** — via STM32duino core (Roger's or official STM32 core)
- **PlatformIO** — with STM32 framework support
- **MicroPython** — community-supported STM32 port
- **Rust** — embedded Rust with stm32f1xx-hal crate
- **Zephyr RTOS** — supported target board

## Debugging

The Blue Pill supports Serial Wire Debug (SWD) via an external ST-Link programmer. This enables full step-through debugging, breakpoints, and variable inspection — a significant advantage over serial-only debugging on Arduino boards.

## Common Considerations

- Some Blue Pill clones use counterfeit STM32 chips (CKS32 or CS32) with slightly different behavior
- The onboard USB pull-up resistor (R10) often needs replacement (1.5k instead of 10k) for reliable USB connectivity
- Despite being a "64 KB" chip, most STM32F103C8T6 units have 128 KB of accessible flash

## Use Cases

The Blue Pill excels in projects requiring real-time performance, multiple communication buses, or more GPIO than an Arduino Uno, all at a very low price point.

## Where to Buy

- [OpenELab](https://openhardware.directory/r?to=https%3A%2F%2Fopenelab.io%2Fproducts%2Fbluepilldevelopmentboard&ref=openhardware.directory&product=blue-pill-stm32&source=md-export) — $2.50

## Resources

- [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fen%2Fmicrocontrollers-microprocessors%2Fstm32f103c8.html&ref=openhardware.directory&product=blue-pill-stm32&source=md-export)
- [datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.st.com%2Fresource%2Fen%2Fdatasheet%2Fstm32f103c8.pdf&ref=openhardware.directory&product=blue-pill-stm32&source=md-export)
- [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2Fstm32duino%2FArduino_Core_STM32&ref=openhardware.directory&product=blue-pill-stm32&source=md-export)

## Tags

`stm32`, `arm`, `cortex-m3`, `microcontroller`, `arduino`, `embedded`, `swd`

## Images

![Blue Pill STM32F103C8T6](https://nbg1.your-objectstorage.com/openhardware-directory/entities/blue-pill-stm32/be19891ddb8a.jpg)
![Blue Pill STM32F103C8T6](https://nbg1.your-objectstorage.com/openhardware-directory/entities/blue-pill-stm32/941afe0afff1.jpg)
![Blue Pill STM32F103C8T6](https://nbg1.your-objectstorage.com/openhardware-directory/entities/blue-pill-stm32/4825a44d3092.jpg)
![Blue Pill STM32F103C8T6](https://nbg1.your-objectstorage.com/openhardware-directory/entities/blue-pill-stm32/260535cc68f9.jpg)
![Blue Pill STM32F103C8T6](https://nbg1.your-objectstorage.com/openhardware-directory/entities/blue-pill-stm32/18d290c8cdc8.jpg)

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