ME Labs, Inc. | 1-719-520-5323 | Example Program - CLOCKX4.pbp

' Name        : CLOCKX4.pbp
' Compiler    : PICBASIC PRO Compiler 2.6
' Assembler   : PM or MPASM
' Target PIC  : PIC12F683
' Hardware    : LAB-X4 Experimenter Board
' Oscillator  : 4MHz internal
' Keywords    : ON INTERRUPT, TIMER0
' Description : PICBASIC PRO program for an LCD clock using On Interrupt.
' Uses TMR0 and prescaler.  Watchdog Timer should be set to off at program
' time and Nap and Sleep should not be used. Button may be used to set time.
' Turn off Watchdog Timer and disable reset so button can be used to set clock.
'

LCD     Var GPIO.1  ' LCD TX pin
PB      Var GPIO.3  ' Alias GPIO.3 to push button

T2400 Con 396       ' 2400 baud, true
hour    Var byte    ' Define hour variable
dhour   Var byte    ' Define display hour variable
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
i       Var byte    ' Debounce loop variable

   ANSEL = 0        ' Set all digital
   CMCON0 = 7       ' Analog comparators off

   Pause 500        ' Wait for LCD to startup

   hour = 0         ' Set initial time to 00:00:00
   minute = 0
   second = 0
   ticks = 0
   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
mainloop:
   ' Check button pressed to set time
   If PB = 0 Then
      minute = minute + 1   ' Increment minutes
      If minute >= 60 Then
         minute = 0
         hour = hour + 1
         If hour >= 24 Then
            hour = 0
         Endif
       Endif
       For i = 1 To 100     ' Debounce and delay for 100ms
         Pause 1 ' 1ms at a time so no interrupts are lost
       Next i
       update = 1           ' Set to update screen
   Endif

   ' Check for time to update screen
   If update = 1 Then
      ' Display time as hh:mm:ss
      dhour = hour    ' Change hour 0 to 12
      If (hour // 12) = 0 Then
         dhour = dhour + 12
      Endif

      INTCON = $80    ' No interrupts during Serout2
      ' Check for AM or PM
      If hour < 12 Then
         Serout2 LCD, T2400, [$fe, 1, dec2 dhour, ":", dec2 minute, ":", dec2 second, " AM"]
      Else
          Serout2 LCD, T2400, [$fe, 1, dec2 (dhour - 12), ":", dec2 minute, ":", dec2 second, " PM"]
      Endif
      update = 0      ' Screen updated
      INTCON = $a0    ' Enable TMR0 interrupts
   Endif
   Goto mainloop      ' Do it all forever


   ' 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 elasped - update time
   ticks = 0
   second = second + 1
   If second >= 60 Then
       second = 0
       minute = minute + 1
       If minute >= 60 Then
          minute = 0
          hour = hour + 1
          If hour >= 24 Then
             hour = 0
          Endif
        Endif
   Endif
   update = 1      ' Set to update LCD

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

   End

           

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