'**************************************************************
'
'  Rotary Encoder Counter Program for Wheelchair
'
'    2000/12/21 Koichi Hirata
'
'    wchairb.bas
'
'**************************************************************
'
' for AT90S2313-10PC
' 12bits Output
'
'*********************
' Initial set
'*********************
'
Config Portb = Output
Config Pind.0 = Input
Config Pind.1 = Input
Config Pind.2 = Output
Config Pind.3 = Output
Config Pind.4 = Output
Config Pind.5 = Output
Config Pind.6 = Output
Config Pind.7 = Output
Dim A As Byte                                                 '0 - 255
Dim C As Integer                                              '-32767 - +32768
Dim D As Integer                                              '-32767 - +32768
A = 0
C = 0
' 
'*********************
' Sencing (Loop)
'*********************
'
Do
  If A = 0 And Pind.0 = 0 Then
    A = 1
  End If
  If A = 1 And Pind.0 = 1 Then                                'Up pulse
    A = 2
    If Pind.1 = 1 Then
      C = C + 1
    End If
    If Pind.1 = 0 Then
      C = C - 1
    End If
    If C = -1 Then
      C = 4095
    End If
    If C = 4096 Then
      C = 0
    End If
'
    D = C
    If D => 2048 Then
      Portd.5 = 1
      D = D - 2048
    Else
      Portd.5 = 0
    End If
    If D => 1024 Then
      Portd.4 = 1
      D = D - 1024
    Else
      Portd.4 = 0
    End If
    If D => 512 Then
      Portd.3 = 1
      D = D - 512
    Else
      Portd.3 = 0
    End If
    If D => 256 Then
      Portd.2 = 1
      D = D - 256
    Else
      Portd.2 = 0
    End If
    If D => 128 Then
      Portb.7 = 1
      D = D - 128
    Else
      Portb.7 = 0
    End If
    If D => 64 Then
      Portb.6 = 1
      D = D - 64
    Else
      Portb.6 = 0
    End If
    If D => 32 Then
      Portb.5 = 1
      D = D - 32
    Else
      Portb.5 = 0
    End If
    If D => 16 Then
      Portb.4 = 1
      D = D - 16
    Else
      Portb.4 = 0
    End If
    If D => 8 Then
      Portb.3 = 1
      D = D - 8
    Else
      Portb.3 = 0
    End If
    If D => 4 Then
      Portb.2 = 1
      D = D - 4
    Else
      Portb.2 = 0
    End If
    If D => 2 Then
      Portb.1 = 1
      D = D - 2
    Else
      Portb.1 = 0
    End If
    If D => 1 Then
      Portb.0 = 1
      D = D - 1
    Else
      Portb.0 = 0
    End If
  End If
  If A = 2 And Pind.0 = 0 Then
    A = 0
  End If
Loop
End