Bluepill STM32F103 MCU

Title

Bluepill STM32F103 MCU

What It Is

The Bluepill is a small development board built around an STMicroelectronics STM32F103 ARM Cortex-M3 microcontroller. In this course, it is the main brain of the system.

What It Does In This Project

• runs the course firmware
• talks to sensors and displays
• responds to USB and Bluetooth commands
• manages timers, GPIO, PWM, and communication buses

Origins And Background

The STM32 family comes from STMicroelectronics. It became very popular because it offered a lot of capability for a low cost. The Bluepill board became well known in hobby and education circles because it made ARM microcontrollers cheap and accessible.

How It Communicates

• UART for HC-05 serial communication
• I2C for devices like the MPU6050
• SPI for devices like the MAX7219
• USB CDC for the browser dashboard serial connection
• GPIO pins for direct digital input and output

Course Pinout

These are the main Bluepill connections used in the course hardware:

• PA4 : MAX7219 CS
• PA5 : MAX7219 SCK
• PA7 : MAX7219 MOSI
• PA8 : WS2812 RGB matrix data using TIM1_CH1
• PA2 : HC-05 TX line on USART2
• PA3 : HC-05 RX line on USART2
• PB10 : I2C2 SCL for MPU6050 and SSD1306 OLED
• PB11 : I2C2 SDA for MPU6050 and SSD1306 OLED
• PB1 : MPU6050 INT
• PB4 : HC-SR04 TRIG
• PB0 : HC-SR04 ECHO
• PA11 : USB D-
• PA12 : USB D+

This is a good note to keep beside the bench, because the Bluepill is where all the separate device notes come together.

Physical Layer Notes

The MCU sends and receives electrical signals on pins. Some pins are simple on/off digital lines. Others are shared buses with timing rules and special modes.

Why It Matters

This board shows students that a microcontroller is not just “a tiny computer”. It is a computer designed to interact directly with real hardware.

Teaching Focus

• microcontroller vs full computer
• firmware in flash, working data in RAM
• pins, peripherals, and datasheets
• the idea of one chip talking to many devices

Datasheet Navigation Tips

When using the STM32 datasheet or reference manual, look for:

• pinout tables
• memory sizes
• electrical limits
• timer features
• communication peripheral sections

Interesting Detail

The same STM32 chip can blink LEDs, read sensors, talk USB, run timers, and generate PWM all at once because it contains dedicated hardware peripherals for each job.

Good Questions To Ask Students

• Why is a microcontroller better than a full PC for a small robot or gadget?
• Why do we care about which pins can do UART, SPI, or I2C?
• Why does the datasheet matter before wiring something up?