The STM32F103C8T6, commonly called the Blue Pill, is a 32-bit ARM Cortex-M3 microcontroller board running at 72MHz with 64KB flash and 20KB SRAM. It offers 37 GPIO pins, multiple timers, USART, SPI, I2C, USB, and CAN bus.
| Pin | Name | Function | Type |
|---|---|---|---|
| PA0 | PA0/WKUP | ADC0, TIM2CH1, WKUP | ADC |
| PA1 | PA1 | ADC1, TIM2CH2 | ADC |
| PA2 | PA2 | ADC2, TIM2CH3, USART2TX | BUS |
| PA3 | PA3 | ADC3, TIM2CH4, USART2RX | BUS |
| PA4 | PA4 | ADC4, SPI1NSS, DAC1 | ADC |
| PA5 | PA5 | ADC5, SPI1SCK, DAC2 | BUS |
| PA6 | PA6 | ADC6, SPI1MISO, TIM3CH1 | BUS |
| PA7 | PA7 | ADC7, SPI1MOSI, TIM3CH2 | BUS |
| PA8 | PA8 | TIM1CH1, MCO, USB_SOF | I/O |
| PA9 | PA9 | USART1TX, TIM1CH2 | BUS |
| PA10 | PA10 | USART1RX, TIM1CH3 | BUS |
| PA11 | PA11 | USB_DM, CAN_RX | BUS |
| PA12 | PA12 | USB_DP, CAN_TX | BUS |
| PA13 | PA13 | SWDIO (debug) | I/O |
| PA14 | PA14 | SWCLK (debug) | I/O |
| PA15 | PA15 | SPI1NSS, TIM2CH1 | I/O |
| PB0 | PB0 | ADC8, TIM3CH3 | ADC |
| PB1 | PB1 | ADC9, TIM3CH4 | ADC |
| PB5 | PB5 | SPI1MOSI, I2C1SMBA | BUS |
| PB6 | PB6 | I2C1SCL, TIM4CH1 | BUS |
| PB7 | PB7 | I2C1SDA, TIM4CH2 | BUS |
| PB8 | PB8 | I2C1SCL, TIM4CH3, CAN_RX | BUS |
| PB9 | PB9 | I2C1SDA, TIM4CH4, CAN_TX | BUS |
| PB10 | PB10 | I2C2SCL, USART3TX | BUS |
| PB11 | PB11 | I2C2SDA, USART3RX | BUS |
| 3V3 | 3V3 | 3.3V power | PWR |
| GND | GND | Ground | GND |
| 5V | 5V | 5V input | PWR |
| NRST | NRST | Reset, active low | I/O |