shiyan.c

单片机和cpld综合应用的示例

#include <reg51.h>
#define key_wr 0xff00
#define key_rd 0xff01

 viod  wr_cpld( unsigned int addr, unsigned char data);
unsigned char rd_cpld( unsigned int addr);
viod getkey( unsigned char keyin);

unsigned char led_buf;

viod main(viod)
{
  unsigned char key_buf,buffer;
  key_buf = 0xff;
   led_buf = 0xff;
 while(1)
  {
    buffer = rd_cpld(key_wr);
if( ! ( key_buf == buffer) && (buffer != 0xff))
 {
   key_buf =buffer;
   getkey(key_buf);
   wr_cpld(led_wr,led_buf);
}
}
}
 
viod getkey(unsigned char keyin)
{
switch (keyin)
{
 case 0xfe:
   led_buf = 0xf9;
   break;
 case 0xfd:
   led_buf = 0xa4;
   break;
case 0xfb:
   led_buf = 0xb0;
   break;
case 0xf7:
   led_buf = 0x99;
   break;
case 0xef:
   led_buf = 0x92;
   break;
case 0xdf:
   led_buf = 0x82;
   break;
case 0xbf:
   led_buf = 0xf8;
   break;
case 0x7f:
   led_buf = 0x80;
   break;
default:
   led_buf = 0xc0;
   break;
}
}

viod wr_cpld(unsigned int addr)
{
  *((unsigned char xdata * ) addr)=data;
}

unsigned char rd_cpld (unsigned int addr)
{
return * ((unsigned char xdata * ) addr);
}