How to Use stm32f103: Examples, Pinouts, and Specs

The STM32F103, manufactured by Bala (Part ID: 123), is a high-performance microcontroller from the STM32 family. It is based on the ARM Cortex-M3 core, offering a 32-bit architecture with advanced features and integrated peripherals. This microcontroller is designed for applications requiring efficient processing, low power consumption, and versatile connectivity.

• Embedded systems and IoT devices
• Industrial automation and control systems
• Motor control and robotics
• Consumer electronics
• Medical devices
• Data acquisition and signal processing

The STM32F103 microcontroller is packed with features that make it suitable for a wide range of applications. Below are its key technical specifications:

• Core: ARM Cortex-M3, 32-bit RISC architecture
• Operating Frequency: Up to 72 MHz
• Flash Memory: Up to 128 KB
• SRAM: Up to 20 KB
• GPIO Pins: Up to 37 configurable I/O pins
• Communication Interfaces:
  • 2x I2C
  • 3x USART
  • 2x SPI
  • 1x CAN
• Timers: 3 general-purpose timers, 1 advanced-control timer
• ADC: 12-bit, up to 16 channels
• Operating Voltage: 2.0V to 3.6V
• Power Consumption: Low-power modes available
• Package Options: LQFP48, LQFP64, and others

The STM32F103 comes in various package options. Below is an example pinout for the LQFP48 package:

Refer to the full datasheet for a complete pinout and alternate functions.

The STM32F103 is versatile and can be used in a variety of circuits. Below are the steps and best practices for using this microcontroller:

1. Power Supply: Connect the VDD pin to a 3.3V power source and the VSS pin to ground. Ensure the power supply is stable and within the operating voltage range.
2. Clock Configuration: Use an external crystal oscillator (e.g., 8 MHz) connected to the OSC_IN and OSC_OUT pins for precise timing, or configure the internal RC oscillator.
3. Programming: Use an ST-Link programmer or a USB-to-serial adapter to upload firmware via the USART1 interface or SWD (Serial Wire Debug) pins.
4. Peripherals: Configure GPIO pins and peripherals (e.g., UART, SPI, I2C) in the firmware using the STM32 HAL (Hardware Abstraction Layer) or CMSIS libraries.
5. Reset: Connect a pull-up resistor (10 kΩ) to the NRST pin for proper reset functionality.

• Decouple the power supply with capacitors (e.g., 0.1 µF and 10 µF) near the VDD pin to reduce noise.
• Use proper pull-up or pull-down resistors for unused GPIO pins to avoid floating states.
• Ensure proper grounding and PCB layout to minimize EMI and improve signal integrity.
• Use the STM32CubeMX tool to generate initialization code and configure peripherals easily.

The STM32F103 can communicate with an Arduino UNO via UART. Below is an example code for the Arduino side:

// Arduino UNO code to communicate with STM32F103 via UART
#include <SoftwareSerial.h>

// Define RX and TX pins for SoftwareSerial
SoftwareSerial mySerial(10, 11); // RX, TX

void setup() {
  // Initialize serial communication
  Serial.begin(9600); // Arduino's default serial port
  mySerial.begin(9600); // SoftwareSerial for STM32 communication

  Serial.println("Arduino ready to communicate with STM32F103");
}

void loop() {
  // Send data to STM32
  mySerial.println("Hello STM32!");

  // Check if data is received from STM32
  if (mySerial.available()) {
    String data = mySerial.readString();
    Serial.print("Received from STM32: ");
    Serial.println(data);
  }

  delay(1000); // Wait for 1 second
}

1. Microcontroller Not Powering On

   • Cause: Incorrect power supply or missing decoupling capacitors.
   • Solution: Verify the power supply voltage (2.0V-3.6V) and add decoupling capacitors near the VDD pin.

2. Unable to Program the Microcontroller

   • Cause: Incorrect connection to the programmer or wrong boot mode.
   • Solution: Check the SWD or USART1 connections and ensure the BOOT0 pin is set correctly.

3. Peripheral Not Responding

   • Cause: Incorrect pin configuration or clock settings.
   • Solution: Double-check the pin assignments and ensure the peripheral clock is enabled in the firmware.

4. High Power Consumption

   • Cause: Unused peripherals or GPIO pins left floating.
   • Solution: Disable unused peripherals and configure unused GPIO pins as analog inputs.

Q: Can the STM32F103 operate at 5V?
A: No, the STM32F103 operates within a voltage range of 2.0V to 3.6V. Use a level shifter for 5V systems.

Q: How do I debug the STM32F103?
A: Use the SWD interface with an ST-Link debugger and software like STM32CubeIDE or Keil uVision.

Q: What is the maximum clock speed of the STM32F103?
A: The maximum clock speed is 72 MHz when using an external crystal oscillator.

Q: Can I use the STM32F103 for low-power applications?
A: Yes, the STM32F103 supports multiple low-power modes, including sleep and standby, to reduce power consumption.

This concludes the documentation for the STM32F103 microcontroller. For more details, refer to the official datasheet and reference manual.