Interrupts and Sleep help 16f818

[Tabsoft]

Andy,

You are correct that your timeout1 test/calculation will fail when the RTC roles over from 59 to 00.
Also, if for some reason that the execution is delayed you could miss an entire minute which would further affect your timeout1 test.

I took the liberty of adding/modifying the logic to make this portion more robust (although I can't test this :-) )
Take a look at the revised code and see if this helps you.

' Name        : PI.pbp
' Compiler    : PICBASIC PRO Compiler 2.5
' Assembler   : MPASM
' Target PIC  : PIC16F628A or similar type
' Hardware    : VeroBoard
' Oscillator  : 4Megs Internal
' Keywords    : I2CREAD, I2CWRITE, LCDOUT
' Description : PICBASIC PRO program for an LCD clock program
' using the Dallas DS1307 I2C RTC.


' Define LCD pins
        DEFINE LCD_EREG PORTA
        DEFINE LCD_EBIT 6

' Alias pins
        SDA Var PORTB.1
        SCL Var PORTB.4
        wakebutton var PORTB.0 'shake
        lcdandrtc var PORTA.6 'LCD and RTC ON/OFF
        timeout1 var byte
        'timeout2 var byte
        PrevTime var byte     'Holds previously read RTCMin
        CurTime  var byte     'Holds currently read RTCMin
        TimeoutMax var byte 'You can change this to a constant if it is not changed during execution
        WakeupFlag var bit    'Used for wakeup/reset tracking for timer
        
        TimeoutMax = $02    'You can delete this if TimeoutMax is a constant
        WakeupFlag = 1        'Preset to true
        
' Allocate variables
        RTCYear  Var Byte
        RTCMonth Var Byte
        RTCDate  Var Byte
        RTCDay   Var Byte
        RTCHour  Var Byte
        RTCMin   Var Byte
        RTCSec   Var Byte
        RTCCtrl  Var Byte
     
        TRISA=0 'outputs
        TRISB=15 'Bit 0,1,2,3 inputs
        CMCON=7 'turns  off analogs
        
        
        
wakeup: INTCON=%00010000 'RB0 is interrupt
        OPTION_REG.6=0 'Trig on falling
        OPTION_REG.7=0 'Enables pull ups       
        Pause 500            ' Wait for LCD to startup
        Lcdout $fe, 1 ' Clear LCD screen
        Lcdout "WELCOME TO"  ' Display WELCOME TO 
        Lcdout $fe, $C0, "      PI DAY" ' Display  PI Day
        Pause 2000       ' Wait 2 seconds
        Lcdout $fe, 1 ' Clear LCD screen
        
        
        timeout1 = TimeoutMax   'Preset timeout1 for countdown
        
        'Set initial time 
        RTCYear = $15
        RTCMonth = $03
        RTCDate = $03
        RTCDay = $06
        RTCHour = $20
        RTCMin = $46
        RTCSec = 0
        RTCCtrl = 0
        'Gosub settime        ' Set the time
        Goto mainloop        ' Skip over subroutines

' Subroutine to write time to RTC

'settime:I2CWrite SDA, SCL, $D0, $00, [RTCSec, RTCMin, RTCHour, RTCDay, RTCDate, RTCMonth, RTCYear, RTCCtrl]
'        Return

' Subroutine to read time from RTC
        
gettime:I2CRead SDA, SCL, $D0, $00, [RTCSec, RTCMin, RTCHour, RTCDay, RTCDate, RTCMonth, RTCYear, RTCCtrl]
        'timeout1=rtcmin
        CurTime = RTCMin    '
        if WakeupFlag = 1 then  '1st time after a wakeup/reset
            PrevTime = CurTime  'Set PrevTime after wakeup/reset
            WakeupFlag = 0        'Clear the flag
        endif
        
        Return

' Main program loop 
        
mainloop:
        Gosub gettime        ' Read the time from the RTC

        ' Display time on LCD
        'Lcdout $fe, 1, hex2 RTCMonth, "/", hex2 RTCDate, "/" , hex2 RTCYear,_
        '"  ", hex2 RTCHour, ":", hex2 RTCMin, ":", hex2 RTCSec

        Lcdout $fe, 1, HEX2 RTCDate, "/", HEX2 RTCMonth,"   ", HEX2 RTCHour, ":", HEX2 RTCMin, ":", HEX2 RTCSec
        
        IF RTCHour <=$12 then  gosub morning
        IF RTCHour >=$13 then  gosub afternoon
        
        IF RTCHour=$03 and RTCMin=$14 Then CACHE ' Morning Cache
        IF RTCHour=$15 and RTCMin=$14 Then CACHE ' Afternoon Cache
        
        
        'if rtcmin=(timeout1+2) then bedtime
        If CurTime > PrevTime Then
            timeout1 = timeout1 - (CurTime - PrevTime)
            PrevTime = CurTime
        else
            'Oops something happened. Current time is less than Previous time
            'This should take care of the rollover from 59 to 00 minutes and unexpected delays
            'If timeout1 = 0 no need to do anything, the timeout1 test below will put the unit to sleep
            'The WakeupFlag will be set when we go to sleep and PrevTime and CurTime will be set properly
            'after we wakeup and proceed through the mainloop
            if timeout1 > 0 then
                timeout1 = timeout1 - 1 'decrement the timeout value
                PrevTime = CurTime  'Reset Previous time to a valid number for the countdown timer
            endif
        endif
        
        if timeout1 = 0 then    'Timeout reached
            WakeupFlag = 1     'Reset the flag
            goto bedtime        'countdown has reached 0, go to sleep
        endif
        
        Pause 500            ' Do it about 2 times a second
        Goto mainloop        ' Do it forever
        
morning:    Lcdout $fe, $C0, "CACHE @  3:14AM"
        return
        
afternoon:  Lcdout $fe, $C0, "CACHE @ 3:14PM" 
        return
        
CACHE:  Lcdout $fe, 1 ' Clear LCD screen
        LCDOUT "CONGRATULATIONS"
        Lcdout $fe, $C0, "CACHE IS LOCATED"
        PAUSE 2000
        Lcdout $fe, 1 ' Clear LCD screen
        Lcdout "N   XX",$DF, "  YY.ZZZ "  ' Display N   123° 456.789
        Lcdout $fe, $C0, "W   XX",$DF, "  YY.ZZZ " ' Display  W   123° 456.789
        PAUSE 20000
         
bedtime:high lcdandrtc 'turn of lcd and rtc
        INTCON.1=0 'reset RB0 interupt flag
        @ sleep
        @ NOP
        @ NOP
        pause 500 'wakeup delay
        goto wakeup
        
        end

[andybarrett1]

Missed this...

Thanks TABSoft..... Will try later.

Let you know how I get on

BR
Andy