蜂鸣器与继电器

 蜂鸣器：有源蜂鸣器和无源蜂鸣器，有源蜂鸣器只需通电即可使用，无源蜂鸣器则需要输入高低电平的方波才能发出声音，蓝桥杯单片机板子采用的是有源蜂鸣器，高电平工作，低电平不工作。

继电器：有一个L10指示灯，继电器声音很小不容易听到，可以观察指示灯判断状态。

#include "stc15f2k60s2.h"
#include "intrins.h"

unsigned char buzzer;
unsigned char relay;

void Delay1000ms()		//@12.000MHz
{
	unsigned char i, j, k;

	_nop_();
	_nop_();
	i = 46;
	j = 153;
	k = 245;
	do
	{
		do
		{
			while (--k);
		} while (--j);
	} while (--i);
}

void Device_Ctrl(unsigned char postion,unsigned char dat)
{
	P0 = dat;
	P2 = postion;
	P2 = 0x00;
}
void System_Init(void)
{
	buzzer = 0;
	relay = 0;
	Device_Ctrl(0xa0,(buzzer<<6)|(relay<<4));
}

void main(void)
{
	System_Init();
	while(1)
	{
		buzzer = 1;
		relay = 0;
		Device_Ctrl(0xa0,(buzzer<<6)|(relay<<4));
		Delay1000ms();
		buzzer = 0;
		relay = 1;
		Device_Ctrl(0xa0,(buzzer<<6)|(relay<<4));
		Delay1000ms();
	}

}