ch451_ad键盘查询.c

ch451控制键盘自动扫描芯片

#include<reg51.h>
#define CH451_SYSOFF    0x0402		   //设定系统参数，开显示,关键盘
#define CH451_RESET     0X0201             //设定复位
#define CH451_KEY       0x07ff		   //读取键码
unsigned char keycode,num;                       //定义存放采样数据的寄存器
sbit dout=P1^3;
sbit dclk=P1^0;
sbit din=P1^1;
sbit load=P1^2;
void write(unsigned int order);
void ch451_read();

main()
 {  
   din=1;                                 //通知CH451使能四个串行口
   din=0;
   din=1;
   num=0;
   write(CH451_RESET);                    //设定复位
   write(CH451_SYSOFF);                   //设定系统参数
 while(1)
   { ch451_read();
    if(keycode==0x40)
       { num++;
         keycode=0xff;}
   }
 }


void write(unsigned int order)      //数据输入到CH451子程序
  {
     unsigned int i;
     load=1;
   for(i=0;i<12;i++)
     {
       din=order&1;
       dclk=0;
       order=order>>1;
       dclk=1;
     }
   load=0;
   load=1;
  }


void ch451_read()
{ unsigned int i;
  load=1;
  while(dout==1);
  write(CH451_KEY);
  load=1;
  load=0;
  load=1;
  keycode=0x00;
    for(i=0;i<6;i++)
     {
     keycode=keycode|(unsigned char)dout;
     keycode=keycode<<1;
     dclk=1;
     dclk=0;
     }
     keycode=keycode|(unsigned char)dout;
     for(i=0;i<42500;i++);
    din=1;                                 //通知CH451使能四个串行口
    din=0;
   din=1;
   dout=1;
   write(CH451_RESET);                    //设定复位
   write(CH451_SYSOFF);                   //设定系统参数 
}