#include <stdint.h>

/* Base addresses (STM32C0 series) */
#define RCC_BASE        0x40021000UL
#define GPIOB_BASE      0x50000400UL

/* RCC registers */
#define RCC_IOPENR      (*(volatile uint32_t *)(RCC_BASE + 0x34))

/* GPIOB registers */
#define GPIOB_MODER     (*(volatile uint32_t *)(GPIOB_BASE + 0x00))
#define GPIOB_ODR       (*(volatile uint32_t *)(GPIOB_BASE + 0x14))


/* Delay function */
void delay(volatile uint32_t d)
{
    while (d--);
}

int main(void)
{
    /* 1. Enable GPIOB clock (bit 1) */
    RCC_IOPENR |= (1 << 1);

    //2. Configure PB1-15 as output//
    
    GPIOB_MODER = 0x00000000;
    GPIOB_MODER = 0x55555555;


    while (1)
    {
      // Toggle LED//
      GPIOB_ODR ^= 0xFFFF;

      delay(300000);
    }
}