How to Use STM32F103C8T6 Blue Pill: Examples, Pinouts, and Specs

The STM32F103C8T6 Blue Pill is a compact and affordable microcontroller board based on the STM32F103C8T6 chip. It features a 32-bit ARM Cortex-M3 core, 64KB of flash memory, and a wide range of I/O pins, making it a versatile choice for embedded systems and IoT projects. Its small form factor and low cost make it popular among hobbyists and professionals alike.

• Robotics and automation systems
• IoT devices and smart home applications
• Data acquisition and sensor interfacing
• Prototyping and educational projects
• Motor control and signal processing

The STM32F103C8T6 Blue Pill has a total of 40 pins, including power, ground, and I/O pins. Below is a summary of the pin configuration:

1. Powering the Board:

   • Connect the board to a 5V power source via the USB port or supply 3.3V directly to the 3.3V pin.
   • Ensure the ground (GND) pin is connected to the circuit's ground.

2. Programming the Board:

   • Use a USB-to-Serial adapter or an ST-Link programmer to upload code.
   • Set the BOOT0 pin to 1 (high) for programming mode and back to 0 (low) for normal operation.

3. Connecting Peripherals:

   • Use the GPIO pins for interfacing with sensors, actuators, or other devices.
   • For analog inputs, connect sensors to the A0-A7 pins.
   • For communication, use the UART, SPI, or I2C pins as needed.

4. Flashing Code:

   • Install the STM32CubeIDE or Arduino IDE with the STM32 core.
   • Write your code and upload it to the board using the appropriate programmer.

• Always use a voltage level shifter when interfacing 5V devices with the 3.3V GPIO pins.
• Avoid drawing more than 25mA from any GPIO pin to prevent damage.
• Use decoupling capacitors near the power pins to reduce noise.
• Ensure proper grounding to avoid erratic behavior in high-speed applications.

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

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

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

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

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

1. Board Not Detected by Programmer:

   • Ensure the BOOT0 pin is set to 1 for programming mode.
   • Check the USB cable and connections.
   • Verify that the correct COM port is selected in the IDE.

2. Code Upload Fails:

   • Ensure the correct board and programmer are selected in the IDE.
   • Press the reset button before uploading the code.

3. GPIO Pins Not Responding:

   • Check for proper pinMode configuration in the code.
   • Verify that the connected device is functioning correctly.

4. Board Overheating:

   • Ensure the power supply voltage does not exceed the recommended range.
   • Avoid drawing excessive current from the GPIO pins.

Q: Can I use the STM32F103C8T6 Blue Pill with the Arduino IDE?
A: Yes, you can use the Arduino IDE by installing the STM32 core. Follow the instructions on the STM32 Arduino GitHub page.

Q: What is the maximum clock speed of the Blue Pill?
A: The maximum clock speed is 72 MHz.

Q: How do I select between USB and UART for programming?
A: Use the BOOT0 pin to select the boot mode. For USB programming, ensure the correct drivers are installed.

Q: Can I power the board with 5V?
A: Yes, you can power the board via the USB port or the 5V pin. However, the GPIO pins operate at 3.3V, so use level shifters if interfacing with 5V devices.