'****************************************************************
'*  Name    : OXO1.BAS                                          *
'*  Author  : Joe Farr                                          *
'*  Notice  : Copyright (c) 2008 Knight COmputer Services Ltd   *
'*          : All Rights Reserved                               *
'*  Date    : 25/10/2008                                        *
'*  Version : 1.0                                               *
'*  Notes   : Source code for the OXO board hardware test       *
'*          :                                                   *
'****************************************************************

' Which Microchip PIC are we using
Device 16F887 

' This sets the oscilator configuration to use the internal one
@CONFIG_REQ
@__CONFIG _CONFIG1, INTRC_OSC_CLKOUT & WDT_OFF & DEBUG_OFF & FCMEN_OFF & IESO_OFF & BOR_OFF & LVP_OFF & CPD_OFF & CP_OFF & MCLRE_OFF & PWRTE_ON
@__CONFIG _CONFIG2, WRT_OFF & BOR21V 

XTAL = 4 
ALL_DIGITAL TRUE ' All I/O Ports are digital - Logic 1's or 0's

    ' We need some variables
    ' ALWAYS declare your variables at the start of the program. (The above instructions are for the compiler and don't generate any actual program code)
    Dim nRow        As Byte
    Dim nCol        As Byte   
    Dim nDelay      As Byte 

    ' Bytes are 8 bits and can hold a value 0 to 255.
    ' There are many types of variables but try and declare your variables in size order - largest first
    ' as the compiler is more efficient.


    ' Next, we need to configure the PIC's input / output ports/    
    
    ' *** PORTC - This drives the OXO columns - There are 6 colums ((0)Red (1)Green, (2)Red (3)Green, (4)Red (5)Green)
    Symbol Columns  = PORTC ' Give our port a meaningful name - Columns
    Output Columns ' Even tho we don't use all of PORTC, we set ALL of it to being an output.
        
    ' *** PORTD - This drives the OXO rows - There are 3 rows (Top, middle and bottom)
    Symbol Rows     = PORTD ' Give our port a meaningful name - Rows
    Output Rows
    
    ' *** PORTE - We have connected our switches here... 
    Symbol Switches = PORTE
    Input Switches  

    ' Some notes on driving the OXO board.
    ' The board consists of 18 LEDs - 9 Red and 9 Green (Actually there are 9 physical LEDs - each with 2 colours)
    ' To light a LED, it must be given a small voltage. One of it's pins must be connected to +, and one pin to -.
    ' If both pins are connected to either + or -, OR the + and - are applied to the LED the wrong way around, it won't light.
    '
    ' The board is formed from a matrix. 
    ' A traditional board of course is made from a 3 x 3 matrix, but in this case, each "cell" on the board
    ' has to have 2 LED's (1 x Red, 1 x Green). 
    ' To accomplish this, there are actually colums(0 To 5) and 3 Rows (0 To 2).
    ' To light the centre RED Led, column 2 must be set to +, and row 1 must be set to -.
    '
    '
    ' There are 2 switches for you to use. They are connected to bits 0 and 1 of PORT E
    ' When a switch is pressed, it's associated bit will go to logic 1 and then back to 0 when you release it.
    ' 
    ' The sample code below cycles though every LED in turn. Looking at the pattern displayed and reading the 
    ' code should explain how everything works.        
    
      
    nDelay = 128
      
Again:
                                        
    For nCol = 0 To 5    
        Low Columns ' All off
        SetBit Columns, nCol ' Set just the desired bit needed on
                
        For nRow = 0 To 2
            High Rows ' All Off
            ClearBit Rows, nRow ' Set just the desired bit needed on
            DelayMS nDelay
            
            ' Scan to see if a switch has been pressed
            If Switches <> 0 Then 
                ' A switch is pressed
                If Switches.0 = 1 Then 
                    If nDelay + 1 > nDelay Then 
                        Inc nDelay
                        DelayMS 100                       
                    End If
                End If
                If Switches.1 = 1 Then 
                    If nDelay - 1 < nDelay Then 
                        Dec nDelay
                        DelayMS 100
                    End If
                End If                                                
            End If
                
        Next nRow
    Next nCol
                         
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