GPIO (Bare-Metal)

Purpose

Configure and use GPIO without HAL: input/output modes, alternate function mapping, pull-up/down, speed/slew, and pin-change interrupts for LEDs, buttons, and peripheral pin mux.

When to Use

• Blink LED or read button before bringing up UART/SPI
• Mux pins to USART/SPI alternate functions
• EXTI line interrupts on pin edges
• Porting GPIO code between vendors

Workflow

1. STM32 GPIO pattern