发光二极管接口（左端）应为低电平

以LED1为例

LED1的接口为GPB5

void led_init(void)
{
	//配置GPB5功能为输出
	GPBCON &= ~(0x3 << 10);
	GPBCON |= (0x1 << 10);	

	//使GPB5输出高电平(关灯)
	GPBDAT |= (1 << 5);
}

void led_on(void)
{
	GPBDAT &= ~(1 << 5);
}

void led_off(void)
{
	GPBDAT |= (1 << 5);
}

int main(void)
{
//	unsigned int * gpbcon = (unsigned int *)0x56000010;
	
	led_init();
	while(1)
	{
		led_on();
		led_off();
	}

}