#include "stm32c0xx.h"

void delay_ms(uint32_t ms) {
  for (uint32_t i = 0; i < ms * 4000; i++) {
    __NOP();
  }
}

void GPIO_Init(void) {

  RCC->IOPENR |= RCC_IOPENR_GPIOAEN;

 
  GPIOA->MODER &= ~(0x3F);
  GPIOA->MODER |= (0x15);
}

void setLights(int green, int orange, int red) {
  if (green) GPIOA->BSRR = (1 << 0);
  else GPIOA->BRR = (1 << 0);

  if (orange) GPIOA->BSRR = (1 << 1);
  else GPIOA->BRR = (1 << 1);

  if (red) GPIOA->BSRR = (1 << 2);
  else GPIOA->BRR = (1 << 2);
}

int main(void) {
  GPIO_Init();

  while (1) {
    // GREEN
    setLights(1, 0, 0);
    delay_ms(3000);

    // ORANGE
    setLights(0, 1, 0);
    delay_ms(2000);

    // RED
    setLights(0, 0, 1);
    delay_ms(4000);
  }
}