#include <stdint.h>
#include <stm32/stm32f4xx.h>
#include <cmsis/core_cm4.h>

static void watchdog_ack(void)
{
	IWDG->KR = 0xAAAA;
}


int ram_code_main(void)
{
	SysTick_Config(168000UL);
	__enable_irq();
	
	while(1) {
		__WFI();
	}
	
	return 0;
}

void SysTick_Handler(void)
{
	static uint32_t tick_cnt = 0;
	
	tick_cnt++;
	watchdog_ack();
	if (tick_cnt >= 250) {
		GPIOB->ODR ^= (1<<2);
		tick_cnt = 0;
	}
}