#include "stm32c0xx.h"

int main(void) {
    // 1. Enable GPIOA Clock (STM32C0 uses RCC_IOPENR, not AHBENR!)
    RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
    
    // 2. Configure PA5 as Output (GPIOx_MODER)
    GPIOA->MODER &= ~GPIO_MODER_MODE5_Msk;  // Clear MODE5 bits
    GPIOA->MODER |= GPIO_MODER_MODE5_0;     // Set as output (01)
    
    // 3. Set Output Type to Push-Pull (GPIOx_OTYPER)
    GPIOA->OTYPER &= ~GPIO_OTYPER_OT5;      // 0 = Push-pull
    
    // 4. Set Speed to Low (GPIOx_OSPEEDR)
    GPIOA->OSPEEDR &= ~GPIO_OSPEEDR_OSPEED5; // 00 = Low speed
    
    // 5. No Pull-Up/Pull-Down (GPIOx_PUPDR)
    GPIOA->PUPDR &= ~GPIO_PUPDR_PUPD5;      // 00 = No pull
    
    while (1) {
        // 6. Toggle PA5 (GPIOx_ODR)
        GPIOA->ODR ^= GPIO_ODR_OD5;
        
        // 7. Crude Delay
        for (volatile uint32_t i = 0; i < 100000; i++);
    }
}