按键数码管显示实验

要求:能够实现本单片机按下键盘，能够在数码管上显示键盘值。

连线:将片选CS0链接到KEY/LED CS。

#define LEDLen 6


 xdata unsigned char OUTBIT _at_ 0x8002;   // 位控制口
 xdata unsigned char OUTSEG _at_ 0x8004;   // 段控制口
 xdata unsigned char IN     _at_ 0x8001;   // 键盘读入口


 unsigned char LEDBuf[LEDLen];    // 显示缓冲
 code unsigned char LEDMAP[] = {  // 八段管显示码
   0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07,
   0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71
 };


 void Delay(unsigned char CNT)
 {
   unsigned char i;


   while (CNT-- !=0)
     for (i=100; i !=0; i--);
 }


 void DisplayLED()
 {
   unsigned char i;
   unsigned char Pos;
   unsigned char LED;


   Pos = 0x20;       // 从左边开始显示
   for (i = 0; i < LEDLen; i++) {
     OUTBIT = 0;     // 关所有八段管
     LED = LEDBuf[i];
     OUTSEG = LED;
     OUTBIT = Pos;   // 显示一位八段管
     Delay(1);
     Pos >>= 1;      // 显示下一位
   }
 }


 code unsigned char KeyTable[] = {   // 键码定义
   0x16, 0x15, 0x14, 0xff,
   0x13, 0x12, 0x11, 0x10,
   0x0d, 0x0c, 0x0b, 0x0a,
   0x0e, 0x03, 0x06, 0x09,
   0x0f, 0x02, 0x05, 0x08,
   0x00, 0x01, 0x04, 0x07
 };


 unsigned char TestKey()
 {
    OUTBIT = 0;            // 输出线置为0
    return (~IN & 0x0f);   // 读入键状态(高四位不用)
 }


 unsigned char GetKey()
 {
   unsigned char Pos;
   unsigned char i;
   unsigned char k;


   i = 6;
   Pos = 0x20;     // 找出键所在列
   do {
     OUTBIT = ~ Pos;
     Pos >>= 1;
     k = ~IN & 0x0f;
   } while ((--i != 0) && (k == 0));


   // 键值 = 列 x 4 + 行
   if (k != 0) {
     i *= 4;
     if (k & 2)
       i += 1;
     else if (k & 4)
       i += 2;
     else if (k & 8)
       i += 3;


     OUTBIT = 0;
     do Delay(10); while (TestKey());  // 等键释放


     return(KeyTable[i]);  // 取出键码
   } else return(0xff);
 }


 void main()
 {
    LEDBuf[0] = 0xff;
    LEDBuf[1] = 0xff;
    LEDBuf[2] = 0xff;
    LEDBuf[3] = 0xff;
    LEDBuf[4] = 0x00;
    LEDBuf[5] = 0x00;


    while (1) {
      DisplayLED();
      if (TestKey()) LEDBuf[5] = LEDMAP[GetKey() & 0x0f];
    }
 }