/**
 * Main code of firmware
 */
#include "stm32f10x.h"
#include "core_cm3.h"
/* General defines */
#define LED_PORT GPIOC
#define IO_PORT GPIOA
#define BUTTON (1 << 0)
#define LED_BLUE (1 << 8)
#define LED_GREEN (1 << 9)
/* user status flag */
volatile unsigned char status_flag;
void main();
/* Simple delay function */
void delay_ms(unsigned int delay) {
    volatile unsigned int delay_tick = delay * 2000;
    while (delay_tick--);
}
/* chage user flag */
void change_flag(void) {
    status_flag ^= 1;
    delay_ms(100);
}
/* Main function */
void main(void) {
        //status_flag = 0;
        /* setup i/o port c */
        RCC->APB2ENR |= RCC_APB2ENR_IOPCEN;
        LED_PORT->CRH |= GPIO_CRH_MODE8_0 | GPIO_CRH_MODE9_0;
        LED_PORT->CRH &= ~(GPIO_CRH_CNF8 | GPIO_CRH_CNF9);
        /* setup i/o port a */
        RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_AFIOEN;
        /* setup AFIO andEXTI */
        AFIO->EXTICR[0] |= AFIO_EXTICR1_EXTI0_PA;
        EXTI->IMR |= (1 << 0);
        EXTI->FTSR |= (1 << 0);
        /* enable EXTI0 interrupt */
        NVIC_EnableIRQ(EXTI0_IRQn);
        /* enable leds */
        LED_PORT->ODR = LED_BLUE;// | LED_GREEN;
        /* infinity loop */
        //while (1);
        while (1) {
            if (status_flag & 1) {
                /* disable leds */
                LED_PORT->ODR &= ~LED_BLUE;
                LED_PORT->ODR |= LED_GREEN;
                /* delay ~500ms */
                delay_ms(500);
                /* enable leds */
                LED_PORT->ODR |= LED_BLUE;
                LED_PORT->ODR &= ~LED_GREEN;
                /* delay ~500ms */
                delay_ms(500);
            }
            else {
                /* disable leds */
                LED_PORT->ODR &= ~(LED_BLUE | LED_GREEN);
                /* delay ~500ms */
                delay_ms(500);
                /* enable leds */
                LED_PORT->ODR |= LED_BLUE | LED_GREEN;
                /* delay ~500ms */
                delay_ms(500);
            }
        }
}