;
;  refresh switch input from column driven switch matrix (one 
;  switch tested each interrupt cycle)
;
;  COLPOS is our column position ring counter which will contain one
;  of the following values; 00000001, 00000010, 00000100, 00001000, etc.
;
;       comf    COLPOS,W        ; example ~COL3 = 11110111        |
        andwf   SWKEYS,f        ; indicate switch 'off' (0)
        movf    COLPOS,W        ; example  COL3 = 00001000
        btfss   SWInput         ; is switch at COLPOS 'on' (0)?
        iorwf   SWKEYS,f        ; yes, indicate 'on' (1)

Device = 18F452
Clock = 20

#option _Segment_Port = PORTC                      // Define the 7-Segment PORT
#option _Segment_TRIS = GetTRIS(_Segment_Port)     // Nice way to automatically get the TRIS
                                                   //  automatically from a selected port
                                                   
Include "ISRTimer.bas"  
Include "utils.bas"

Dim Segment_1_TRIS As TRISD.1,                     // User must define what pins control
    Segment_2_TRIS As TRISD.0,                     //  each segment
    Segment_1 As PORTD.1,
    Segment_2 As PORTD.0            
Dim Number As Byte,                                // Program variables that require no
    Segment_Data As _Segment_Port,                 //  user settings
    Segment_TRIS As _Segment_TRIS,
    Segment_1_Data As Byte,
    Segment_2_Data As Byte

Const
    Timer1 = 0,
    Timer2 = 1
  
// Update_Segments event, multiplex the segment data...
Sub Update_Segments()

    If Segment_1 = 1 Then
        Segment_1 = 0
        Segment_Data = Segment_2_Data
        Segment_2 = 1
    Else
        Segment_2 = 0
        Segment_Data = Segment_1_Data
        Segment_1 = 1    
    EndIf

End Sub

Function Segment_Encode(Segment_Byte As Byte) As Byte  // Convert a byte into segment information
    Select Segment_Byte
    	    Case 0 
    	   	Result = %00111111
    	    Case 1			
    	   	Result = %00000110
    	    Case 2			
    		Result = %01011011
    	    Case 3			
    	   	Result = %01001111
    	    Case 4			
    	   	Result = %01100110
    	    Case 5			
    	   	Result = %01101101 
    	    Case 6			
       		Result = %01111100
    	    Case 7			
     		Result = %00000111
    	    Case 8			
    		Result = %01111111
    	    Case 9			
     		Result = %01100111		 
    	EndSelect
End Function

Sub EncodeSegmentData()                          // Encodes segment data

    Segment_1_Data = Digit(Number,1)             // Extract the first digit & convert it
    Segment_1_Data = Segment_Encode(Segment_1_Data)
    Segment_2_Data = Digit(Number,2)             // Extract the second digit & convert it
    Segment_2_Data = Segment_Encode(Segment_2_Data)

End Sub

// Increment_Number event will increment the register Number
Sub Increment_Number()

    Inc(Number)
    If Number = 100 Then 
        Number = 0
    EndIf
    
    EncodeSegmentData

End Sub

// Start Of Program...
Timer.Initialize(2)                              // initialize the timer module...

// initialise each timer
Timer.Items(Timer1).Interval = 5                 // 5ms
Timer.Items(Timer1).OnTimer = @Update_Segments   // timer1 event handler
Timer.Items(Timer2).Interval = 500               // 500ms
Timer.Items(Timer2).OnTimer = @Increment_Number  // timer2 event handler

Number = 0                                       // Initialize variables
EncodeSegmentData

Segment_TRIS = %00000000                         // Make the segment data lines outputs
Low(Segment_1_TRIS)
Low(Segment_2_TRIS)

Timer.Items(Timer1).Enabled = True               // enable the timers... 
Timer.Items(Timer2).Enabled = True
Timer.Start                                      // start processing all timers...
 
// main program loop...
While True

Wend

Timer.Items(Timer1).Interval = 1                 // 1ms
Timer.Items(Timer1).OnTimer = @Update_Segments   // timer1 event handler

// Update_Segments event, multiplex the segment data...
Sub Update_Segments()

    If Segment_1 = 1 Then
        Segment_1 = 0
        Segment_Data = Segment_2_Data
        Segment_2 = 1
    Else
        Segment_2 = 0
        Segment_Data = Segment_1_Data
        Segment_1 = 1    
    EndIf

End Sub

Inc(Current_Display)                                 //
If Current_Display = 6 Then Current_Display = 0      // Roll over to first display if required
Select Current_Display                               // Find out what data to display
    Case 0
        // Display Seconds_0
    Case 1
        // Display Seconds_1
    Case 2
        // Display Minutes_0
    Case 3
        // Display Minutes_1
    Case 4
        // Display Hours_0
    Case 5
        // Display Hours_1
EndSelect