guess2.c

这是HOLTEK HT 48系列单片机应用实例

//4*4 keyboard,software scan
unsigned char _pbc @ 0x15;
unsigned char _pb  @ 0x14;
#define KEYPAD _pb
#define KEYPAD_CTRL _pbc
const unsigned char Scan_Code[16]={0x77,0x7b,0x7d,0x7e,0xb7,0xbb,0xbd,0xbe,0xd7,0xdb,0xdd,0xde,0xe7,0xeb,0xed,0xee};
const unsigned char Display_Code[16]={0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f};
char check_key()
{
 KEYPAD_CTRL = 0x0f;
 KEYPAD=0x7f;
  if(KEYPAD==0x77) return Display_Code[0];
  if(KEYPAD==0x7b) return Display_Code[1];
  if(KEYPAD==0x7d) return Display_Code[2];
  if(KEYPAD==0x7e) return Display_Code[3];
 KEYPAD=0xbf;
  if(KEYPAD==0xb7) return Display_Code[4];
  if(KEYPAD==0xbb) return Display_Code[5];
  if(KEYPAD==0xbd) return Display_Code[6];
  if(KEYPAD==0xbe) return Display_Code[7];
 KEYPAD=0xdf;
  if(KEYPAD==0xd7) return Display_Code[8];
  if(KEYPAD==0xdb) return Display_Code[9];
  if(KEYPAD==0xdd) return Display_Code[10];
  if(KEYPAD==0xde) return Display_Code[11];
 KEYPAD=0xef;
  if(KEYPAD==0xe7) return Display_Code[12];
  if(KEYPAD==0xeb) return Display_Code[13];
  if(KEYPAD==0xed) return Display_Code[14];
  if(KEYPAD==0xee) return Display_Code[15];
 return 0xff;
}