#pragma GCC push_options
#pragma GCC optimize ("O0")

#include "stm32c0xx.h"

void delay_mSeconds(uint32_t mSeconds) {
  SysTick->CTRL = 0;
  SysTick->LOAD = 48000 - 1;
  SysTick->VAL = 0;
  SysTick->CTRL = 7; // Enable SysTick, Enable Interrupt, Use processor clock
  
  for (int i = 0;i < mSeconds; i++){
    while ((SysTick->CTRL & (1 << 16))==0){}
  }

}

unsigned int increment = 0;

void osSystickHandler(void) {
  increment++;
  if(increment == 200){
    GPIOD->ODR ^= (1UL << 2);
    increment = 0;
  }
}

int main(void) {
  // Enable GPIOD clock
  RCC->IOPENR |= RCC_IOPENR_GPIOCEN;

  // Set GPIOD pin 0 as output
  GPIOD->MODER &= ~(3UL << (0 * 2)); // Clear mode
  GPIOD->MODER |=  (1UL << (0 * 2)); // Set to output

  GPIOD->MODER &= ~(3UL << (2 * 2));
  GPIOD->MODER |= (1UL << (2 * 2));



  while (1) {
    GPIOD->ODR ^= (1UL << 0); // Toggle pin 0
    delay_mSeconds(2000);
  }
}