speaker.c

来自「QH_MCU_V1.1单片机C源码. 内含实验程序 这是修改版.」· C语言 代码 · 共 82 行

#include <REG51.H>
#include <sys.h>
#include <intrins.h>
//说明：本实验是当串口接收到0xac后，蜂鸣器开始鸣叫，收到其它数据则停止鸣叫，串口的波特率是19200。
bit  read_flag = 0;
void delay ();
void ISRSER() interrupt 4 using 3
  {
    uchar a;
	 
  if (RI)
    {
	    
       RI = 0;
	   a = SBUF;
      if (a==0xac)
	   read_flag = 1;
	  else 
	    read_flag = 0;
	  SBUF=a;
      while(TI==0);
        TI=0;
    }


  }

void speaker1()
  {
     delay ();
     P2 = 0x10;
     P0 = 0xf7;
     P2 = 0x00;
     P2 = 0x80;
     P0 = 0x01;
	   delay ();
     P0 = 0x00;
     P2 = 0x00;
   }
void main()
{
	P2 = 0x00;
	P0 = 0x00;
  delay();
	SCON |= 0x50;  /* mode 1: 8-bit UART, enable receiver */ 
	TMOD |= 0x20; /* timer 1 mode 2: 8-Bit reload */ 
	PCON |= 0x80; // baud x2
	TH1 = 0xfd;   //串口初始化 0xfd=19200,0xfa=9600,0xf4=4800,0xe8=2400,0xd0=1200  
	TR1 = 1;
	EA = 1;
	ES = 1;  // Turn on Series Interrupte;



	while(1)
	{

	     if (read_flag==1) 

		   {
           
		    speaker1();
		
		   }
   

	}
}

void delay()
{
    uchar i = 0;
	uchar j = 0;
  for (j=0;j<255;j++)
   {
    for (i=0; i<250; i++)
	  ;
   }
}