'/---------------------------------------------------------------------
'/      PROGRAM for VENTILATION FAN CONTROLLER **
'/         AUTHOR:  JAROON KEAWKHRUA
'/                   START   14/10/2542
'/                   UPDATE 14/10/2542
'/        modified from PIC CLOCK.BAS
'/---------------------------------------------------------------------

        Include "bs1defs.bas"

sout    var     portb.3
minute  var     byte    ' Define minute variable
second  var     byte    ' Define second variable
ticks   var     byte    ' Define pieces of seconds variable
update  var     byte    ' Define variable to indicate update of LCD
        th        var     word
        vr        var     word
        comp      var     word
        sen       var     portb.0

        serout sout,n9600,["Hello",10,13]
        minute=0 : second=0 : comp=0
        high porta.2
        low portb.1
        low portb.2

        update = 1      ' Force first display

' Set TMR0 to interrupt every 16.384 milliseconds
        OPTION_REG = $d5        ' Set TMR0 configuration
        INTCON = $a0            ' Enable TMR0 interrupts
        On Interrupt Goto tickint
 

' Main program loop - in this case, it only updates the LCD with the time
mainloop: If update = 1 Then

                ' Display time as hh:mm:ss
SENT:      HIGH SEN
           PAUSE 1
           RCTIME SEN,1,TH   ' use RC time instruction to read POT resistance
            vr = th*8
           vr = vr+50
           if comp => vr then
                low porta.2
                high portb.1
                high portb.2
           endif

           serout sout,n9600,[#minute,":",#second," ",#vr," ",13]  ' used during debugging
                update = 0      ' Screen updated
        Endif

        Goto mainloop
 

' Interrupt routine to handle each timer tick
        disable         ' Disable interrupts during interrupt handler
tickint: ticks = ticks + 1      ' Count pieces of seconds
 
        If ticks < 61 Then tiexit       ' 61 ticks per second (16.384ms per tick)

' One second elapsed - update real-time clock
        ticks = 0

        comp = comp + 1

        second = second + 1
        If second >= 60 Then
                second = 0
                minute = minute + 1
                If minute >= 10 Then
                        minute = 0
                        comp = 0
                        high porta.2
                        low portb.1
                        low portb.2
                Endif
        Endif

        update = 1      ' Set to update LCD

tiexit: INTCON.2 = 0    ' Reset timer interrupt flag
        Resume