How to Use STM32_BluePill: Examples, Pinouts, and Specs

The STM32_BluePill is a compact and affordable development board featuring the STM32F103C8T6 microcontroller. It is widely used in embedded systems and IoT projects due to its powerful ARM Cortex-M3 core, extensive GPIO options, and support for multiple communication protocols. The board includes a USB interface for programming and debugging, making it a versatile choice for both beginners and experienced developers.

• IoT devices and smart home systems
• Robotics and motor control
• Data acquisition and sensor interfacing
• Prototyping and educational projects
• Communication hubs using UART, SPI, or I2C protocols

• Microcontroller: STM32F103C8T6 (ARM Cortex-M3, 32-bit)
• Operating Voltage: 3.3V (logic level)
• Input Voltage: 5V (via USB) or 7-12V (via VIN pin)
• Clock Speed: 72 MHz
• Flash Memory: 64 KB
• SRAM: 20 KB
• GPIO Pins: 37 (16-bit ports: Port A, Port B, and Port C)
• Communication Protocols: UART, SPI, I2C, CAN, USB
• ADC: 12-bit, up to 16 channels
• PWM Outputs: 15 channels
• USB Interface: USB 2.0 Full-Speed
• Dimensions: 53 mm x 22 mm

The STM32_BluePill has a 40-pin layout. Below is the pin configuration:

1. Powering the Board:

   • Use the USB interface (5V) or connect an external power source (7-12V) to the VIN pin.
   • Ensure the board operates at 3.3V logic levels to avoid damage.

2. Programming the Board:

   • Install the STM32CubeIDE or Arduino IDE with STM32 support.
   • Connect the board to your computer via USB or use an external ST-Link programmer.
   • Set the BOOT0 pin to the appropriate position for programming (1 for bootloader mode, 0 for normal operation).

3. Connecting Peripherals:

   • Use GPIO pins for digital input/output.
   • Connect sensors to analog pins (A0-A7) for ADC functionality.
   • Use UART, SPI, or I2C pins for communication with other devices.

4. Flashing Code:

   • Write your code in the IDE and compile it.
   • Upload the code to the board using the USB interface or ST-Link.

• Always check the voltage levels of connected peripherals to ensure compatibility with the 3.3V logic level.
• Use pull-up or pull-down resistors for unused pins to avoid floating states.
• Avoid powering the board via USB and VIN simultaneously to prevent damage.
• Use decoupling capacitors near power pins for stable operation.

Below is an example of blinking an LED connected to pin PC13:

// Include the STM32 library for Arduino
#include <Arduino.h>

// Define the LED pin (PC13 is the onboard LED pin)
#define LED_PIN PC13

void setup() {
  pinMode(LED_PIN, OUTPUT); // Set the LED pin as an output
}

void loop() {
  digitalWrite(LED_PIN, HIGH); // Turn the LED on
  delay(500);                  // Wait for 500 milliseconds
  digitalWrite(LED_PIN, LOW);  // Turn the LED off
  delay(500);                  // Wait for 500 milliseconds
}

1. The board is not detected by the computer:

   • Ensure the USB cable is functional and supports data transfer.
   • Check the BOOT0 pin position (set to 1 for programming mode).
   • Install the correct USB drivers for the STM32.

2. Code upload fails:

   • Verify the correct board and port are selected in the IDE.
   • Ensure the BOOT0 pin is set to the correct position.
   • Try using an external ST-Link programmer if the USB interface fails.

3. Peripherals are not working as expected:

   • Double-check the pin connections and ensure they match the code.
   • Verify the voltage levels of connected devices.
   • Use a multimeter to check for loose or incorrect connections.

• Can I use the STM32_BluePill with the Arduino IDE? Yes, the STM32_BluePill is compatible with the Arduino IDE. Install the STM32 core for Arduino to get started.

• What is the maximum current output of the GPIO pins? Each GPIO pin can source or sink up to 20 mA, but the total current should not exceed 120 mA.

• How do I reset the board? Press the onboard reset button or toggle the RST pin.

• Can I use 5V peripherals with the STM32_BluePill? The STM32_BluePill operates at 3.3V logic levels. Use level shifters for 5V peripherals to avoid damage.

This documentation provides a comprehensive guide to using the STM32_BluePill, ensuring a smooth development experience for your projects.