h27.c

利用伟福 Lab2000P单片机实验仪上提供的显示电路和键盘电路

#define LEDLen 6
#define PB1 2
#define PB0 1

xdata unsigned char OUTBIT _at_ 0x9002;
xdata unsigned char OUTSEG _at_ 0x9004;   // 段控制口
xdata unsigned char IN     _at_ 0x9001;

unsigned char LEDBuf[LEDLen];
unsigned char LEDMAP[] = {
  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, j;
  unsigned char Pos;
  unsigned char LED;

  Pos = 0x20;
  for (i = 0; i < LEDLen; i++) {
    OUTBIT = 0;     // trun off all LED
    LED = LEDBuf[i];
    OUTSEG = LED; 
    OUTBIT = Pos;   // trun on one LED
    Delay(1);
    Pos >>= 1;
  }
}

unsigned char KeyTable[] = {
  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;
   return (~IN & 0x0f);
}

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

  i = 6;
  Pos = 0x20;
  do {
    OUTBIT = ~ Pos;
    Pos >>= 1;
    k = ~IN & 0x0f;
  } while ((--i != 0) && (k == 0));

  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());

    return(KeyTable[i]);
  } else return(0xff);
}

/* ========================================================================================*/

#define ADD 0x0a
#define SUB 0x0b
#define MUL 0x0c
#define DIV 0x0d
#define EQU 0x0e
#define CLR 0x0f

void DisplayResult(signed int Result)
{
  unsigned char i;

  if (Result >= 0) { // 数值大于0
    // 不显示符号位
    LEDBuf[0] = 0;
  } else {
    // 在符号位显示 ‘-’
    LEDBuf[0] = 0x40;
    Result = - Result;
  }

  LEDBuf[1] = 0;
  LEDBuf[2] = 0;
  LEDBuf[3] = 0;
  LEDBuf[4] = 0;
  // 数值对10取模，所得结果为最低位
  LEDBuf[5] = LEDMAP[Result % 10]; Result = Result / 10;
  i = 4;
  // 如果数值除以10后不等于0，继续向高位显示
  while (Result != 0) {
    LEDBuf[i--] = LEDMAP[Result % 10]; Result = Result / 10;
  }
}

void main()
{
  signed int Last, Result;
  unsigned char OP;
  unsigned char Key;

  Last   = 0;
  Result = 0;
  OP     = ADD;

  DisplayResult(Result);
  while (1) {
    while (!TestKey()) DisplayLED();
    // 读取键码
    Key = GetKey();

    if ( (Key >= 0) && (Key <= 9) ) { // 是数字键
      // 输入数值
      Result = Result*10 + Key;
      // 数值送显示缓冲
      DisplayResult(Result);

    } else if (Key == CLR) {   // 是清零键
      // 状态清零
      Last   = 0;
      Result = 0;
      OP     = ADD;
      // 数值送显示缓冲
      DisplayResult(Result);

    } else if ( (Key==ADD) || (Key==SUB) || (Key==MUL) || (Key==DIV) || (Key=EQU) ) {
    // 是功能键
      switch (OP) {  //上一按键是?
        case ADD:
          Result = Last + Result;
          break;
        case SUB:
          Result = Last - Result;
          break;
        case MUL:
          Result = Last * Result;
          break;
        case DIV:
          Result = Last / Result;
          break;
      }
      if (Key == EQU) { // 功能键是‘=’
        // 计算最后结果
        Last = 0;
        OP   = ADD;
      } else { // 是其它功能键
        // 保存结果, 保存按键功能
        Last = Result;
        OP   = Key;
      }
      // 计算值送显示缓冲,
      DisplayResult(Result);
      // 等待下一个数值输入.
      Result = 0;
    }
  }
}