Introduction to STM32

STM32 is a family of 32-bit microcontrollers developed by the STMicroelectronics.
They are based on the ARM Cortex-M processor architecture and are widely used in embedded systems such as automotive electronics, industrial automation, IoT devices, robotics, and consumer electronics.

[!NOTE]
STM32 microcontrollers provide high performance, low power consumption, and a rich set of peripherals, making them ideal for modern embedded applications.

The Three Main Parts of an STM32 System

A typical STM32-based embedded system consists of three main parts:

1. Core (Processor)
2. Peripherals
3. Memory

1. Core (Processor)

The core is the brain of the microcontroller that executes instructions written in C or assembly.

STM32 devices use ARM Cortex-M cores such as:

• Cortex-M0
• Cortex-M3
• Cortex-M4
• Cortex-M7

The core is responsible for:

• Executing program instructions
• Performing arithmetic and logical operations
• Handling interrupts
• Managing system control functions

2. Peripherals

Peripherals are hardware modules integrated inside the STM32 microcontroller that allow interaction with external devices.

Common STM32 peripherals include:

• GPIO (General Purpose Input Output)
• UART / USART
• SPI
• I2C
• ADC (Analog to Digital Converter)
• Timers
• PWM
• CAN communication

These peripherals allow the microcontroller to communicate with sensors, displays, motors, and other hardware components.

3. Memory

STM32 microcontrollers contain different types of internal memory:

• Flash Memory: Stores the program code.
• SRAM: Used for runtime variables and stack.
• EEPROM / Emulated EEPROM: Used for storing non-volatile data.

This memory structure enables efficient execution of embedded applications.

// Example STM32 GPIO Initialization (Bare Metal)

#define GPIOA_BASE 0x48000000
#define GPIOA_MODER (*(volatile unsigned int*)(GPIOA_BASE + 0x00))
#define GPIOA_ODR   (*(volatile unsigned int*)(GPIOA_BASE + 0x14))

void GPIO_Init(void)
{
    // Configure PA5 as output
    GPIOA_MODER |= (1 << 10);
}

void LED_On(void)
{
    GPIOA_ODR |= (1 << 5);
}