'項目：4*4鍵盤1602液晶顯示的計算器
'結果：在proteus仿真運行成功
'時間：2007年8月22日　修正bug
'開發軟件：bascom-avr 11.8.5
'作者：あ邂逅記憶あ
'宜昌AVR單片機　http://ycavr.cn
$regfile = "m16def.dat"
$crystal = 8000000
Config Lcdpin = Pin , Db4 = Porta.4 , Db5 = Porta.5 , Db6 = Porta.6 , Db7 = Porta.7 , E = Porta.3 , Rs = Porta.2
Config Lcd = 16 * 2
Config Kbd = Portc
Cursor Off
Cls

Dim Key As Byte
Dim Oldkey As Byte
Dim Keyvalue As Byte                                        '鍵盤值校正
Dim A As Long                                               '第一個運算數據
Dim B As Long                                               '第二個運算數據
Dim Operator As Byte : Operator = 0                         '運算符標識 1為加2為減3為乘4為除
Dim Resault As Single                                       '運算結果，單精度數。
Dim Error As Bit : Error = 0                                '出錯標志位
Declare Sub Correct()                                       '鍵盤值校正子程序
Declare Sub Account()
Declare Sub Keynum()

Do
   Do
      Oldkey = Getkbd()
      Waitms 20
      Do
         Key = Getkbd()
         Waitms 20
      Loop Until Key <> 16
   Loop Until Key <> Oldkey                                 '取鍵盤值，直到鍵松開為止，防止按住不松，連續出現多個。
   Correct                                                  '鍵盤值校正
   Select Case Key                                          '據校正后的鍵盤值作出相應動作
      Case Is < 3
         Keynum
      Case 3
         If B <> 0 Then Account
         Operator = 4                                       '除運算
      Case Is < 7
         Keynum
      Case 7
         If B <> 0 Then Account
         Operator = 3                                       '乘運算
      Case Is < 11
         Keynum
      Case 11
         If B <> 0 Then Account
         Operator = 2                                       '減運算
      Case 12
         Cls
         Key = 0
         A = 0
         B = 0
         Operator = 0
         Resault = 0
      Case 13
         Keynum
      Case 14
         Account
         Operator = 0
         Resault = 0
      Case 15
         If B <> 0 Then Account
         Operator = 1                                       '加運算
   End Select
Loop
End

Sub Correct()
Select Case Key
   Case 0
      Keyvalue = 7
   Case 1
      Keyvalue = 8
   Case 2
      Keyvalue = 9
   Case 8
      Keyvalue = 1
   Case 9
      Keyvalue = 2
   Case 10
      Keyvalue = 3
   Case 13
      Keyvalue = 0
   Case Else
      Keyvalue = Key
End Select
End Sub

Sub Account()
Select Case Operator
   Case 1
      Resault = A + B
   Case 2
      Resault = A - B
   Case 3
      Resault = A * B
   Case 4
      If B = 0 Then                                         '除數為零，顯示錯誤！
         Cls
         Lcd "B=0"
         Locate 2 , 4
         Lcd "Error !"
         Set Error                                          '置出錯標志位
      Else
         Resault = A / B
      End If
End Select
If Error = 0 Then
   Cls
   Lcd Resault
   A = Resault
   B = 0
Else
   Wait 1
   Cls
   A = 0
   B = 0
   Operator = 0
   Resault = 0
   Reset Error                                              '清出錯標志位
End If
End Sub

Sub Keynum()
Cls
If Operator = 0 Then
   A = A * 10
   A = A + Keyvalue
   Lcd A
Else
   B = B * 10
   B = B + Keyvalue
   Lcd B
End If
End Sub