02-蜂鸣器与继电器的基本控制

由原理图可知:

#include <REGX52.H>

void Delay(unsigned int t) {
	while(t--);
	while(t--);

}

// 74HC138
void _74HC138(unsigned char n) {
	
	switch(n) {   // 0001 1111
		case 4:     // LED使能
			P2 = (P2 & 0x1f) | 0x80;       // Y4 == 1000 0000
			break;
		case 5:   // 蜂鸣器和继电器     // Y5 == 1010 0000
			P2 = (P2 & 0x1f) | 0xa0;
			break;
		case 6:    // 数码管位选       Y6 == 1100 0000
			P2 = (P2 & 0x1f) | 0xc0;
			break;
		case 7:		// 数码管段选  
			P2 = (P2 & 0x1f) | 0xe0;     // Y7 == 1110 0000
			break;
		case 0:
			P2 = (P2 & 0x1f) | 0x00; 
			break;
	
	}

}

void SystemInit(void) {
	// 关闭蜂鸣器和继电器
	_74HC138(5);
	P0 = 0x00;
	// 保持LED为初始状态
	_74HC138(4);
	P0 = 0xff;    // LED低电平点亮
	_74HC138(0);

}
void check_Led(void) {
	unsigned char i;
	_74HC138(4);
	
	
	for(i = 0; i < 8;i++) {  // 1111 1111 << i  1111 1110
		P0 = 0xff << i;
		Delay(10000);
	
	}
	
	for(i = 0; i < 8;i++) { // ~(1111 1111) << i  ===> 1111 1110
		P0 = ~(0xff << i);
		Delay(10000);
	}
	
	_74HC138(0);
}
void cleak_Display(void) {
	unsigned char i;
	_74HC138(7);
	P0 = 0x00;
	for(i =0;i<8;i++) {
		_74HC138(6);         // 1111 1110
		P0 = ~(0xfe << i);  //   0000 0001  0000 0011
		Delay(60000);
	}
	
	for(i = 0; i<8;i++) {
		_74HC138(6);         // 
		P0 = 0xfe << i;  //   1111 1110 
		Delay(60000);
	}
		_74HC138(0);
}

// channel 为74HC138 使能端   dat 为接收的数据
void OutputP0(unsigned char channel,unsigned char dat) {
	_74HC138(channel);
	P0 = dat;

}

void main() {
	unsigned char i;
	//SystemInit();
	//check_Led();
	//cleak_Display();
	SystemInit();
	
	// LED闪烁三遍熄灭
	//_74HC138(4);
	for(i=0;i<3;i++) {
		OutputP0(4,0x00);
		Delay(60000);	
		OutputP0(4,0xff);
		Delay(60000);
	}

	
	//依次点亮LED
	//_74HC138(4);
	for(i = 0;i<8;i++) { 
		OutputP0(4,(0xfe<<i));		
		//P0 = 0Xfe << i; //
		Delay(60000);
	}
	
	
	
	
	// 继电器吸合
	OutputP0(5,0x10); 
	Delay(20000);
	//P0 = 0x00;  
	//Delay(20000);
	
	
	
	// 一次循环熄灭LED
	//_74HC138(4);
	for(i = 0;i<8;i++) {
		OutputP0(4,~(0xfe<<i));			
		//P0 = ~(0Xfe << i); 
		Delay(60000);
	}
	
	
	// 蜂鸣器鸣叫
	OutputP0(5,0x40);
	Delay(20000);
	//P0 = 0x00;  
	//Delay(20000);
	//_74HC138(0); 
	
	
	
	
	
	
}