' program for orienteering control using an iButton (DS1992, DS1993 and up)
' works with PIC16F628

' maximum number of numbered controls: 31 (DS1992), 127 (DS1993) ...
' maximum number of controls in one iButton: 31 (DS1992), 127 (DS1993) ...

' works by dividing memory in 4 byte blocks - every block is one control written in unix timestamp format
' this design is pretty simple, at the cost of smaller number of controls


program Kutijica

' ibutton input ports for version ROUND BOX
'symbol REDLED=1     ' LED flash
'symbol BUZZ=2       ' piezo buzzer
'symbol IBUTTPIN=4   ' ibutton socket

' ### NOTE VERSION RED-LED ###
' ibutton input ports for version HAMMOND BOX

symbol REDLED=0     '0 pin 17 for version 2,
                    '1 pin 18 for version 1
symbol BUZZ=3       ' piezo buzzer
symbol IBUTTPIN=2   '
'

' General
symbol LEDON=0      ' pull-down for on
symbol LEDOFF=1


' controlID - maximum number is 31 (DS1992), 127 (DS1993) ...

dim js as byte[8]
dim js1 as byte[8]
dim js2 as byte[8]

dim counter as byte
dim sec as longword
dim tim as byte
dim crcTest as byte
dim i as byte

dim idBox as byte  ' read from dip switch
dim idBoxLoc as word
dim wasConnected as boolean
dim clockSet as byte



'read some memory
sub procedure Ow_Read_Serial(dim byref PORT as byte, dim pin as byte, dim byref out as byte[8], dim leng as byte)
dim i as byte
dim tmpRead as byte
   i = 0
   while i < leng                    ' we will move 8 bytes
     tmpRead = ow_read(PORT,PIN)     ' get one byte from Dallas iButton
     out[i] = tmpRead                ' move the byte into array
     inc(i)                          ' next i
   wend
end sub




'=======================================================
'CRC8 without table
'All you have to do is to initialise the crc variable (to zero or $FFFF)
' and then call the procedure for every byte of your data.
'=======================================================
sub procedure ByteCRC(dim byref CRC as byte,dim  CRCData as byte)
dim i,TstBit as byte
For i = 0 to 7 ' Do for all 8 bits in data byte
  TstBit = CRC xor CRCData   'CRC.0 xor CRCData.0 ' XOR bit0 of data byte and crc
  TstBit = TestBit(TstBit,0)
  CRCData = CRCData >> 1 ' Position data byte for next bit test
  If TstBit = 1 then  ' If test bit not set, just shift CRC
    CRC = CRC xor $18 ' If set, account for EXOR feedback
  end if ' Shift right the CRC byte
  CRC = CRC >> 1 ' CRC bit 0 to bit bucket
  CRC.7 = TstBit ' Test bit rotates into CRC bit 7
Next i
end sub



' set the PIC clock to real time
sub procedure readTimeFromButton()
dim numOfTries as byte
dim tempSec as longword

    numOfTries=0
      do
        inc(numOfTries)
        ow_reset(PORTA,IBUTTPIN)                     ' onewire reset signal
        ow_write(PORTA,IBUTTPIN,$CC)                 ' write skip read ROM
        ow_write(PORTA,IBUTTPIN,$66)                 ' write to Scratch pad
        Ow_Read_Serial(PORTA,IBUTTPIN,js,5)
       if ((js[4]>$49) and (js[4]<$FF)) then               ' time must be between october 2008 and 2037 (or even 2105 if unsigned)
          sec = ((((js[4] << 8) or js[3])<<8) or js[2] ) <<8 or js[1]  ' set time
          counter=0
          clockSet = 6 ' flash green LED, on the minute for 5 minutes
          PORTA.REDLED = LEDON
          delay_ms(50)
          PORTA.REDLED = LEDOFF
          delay_ms(250)
       end if
       ' loop until seconds are over October 2008 and it's equal to the stuff read from the chip OR the number of tries is over 200
     loop until (((sec>1224736768) and (sec = ((((js[4] << 8) or js[3])<<8) or js[2] ) <<8 or js[1])) or numOfTries>200)
end sub





' write time to button
sub procedure writeTimeToButton(dim location as word)

dim currentTime as longword
dim firstWriteOK as byte
     firstWriteOK=0
     
     if (location>=0) then ' (this statement is redundant)

       ' save current time
       currentTime=sec

      do
       ow_reset(PORTA,IBUTTPIN)                     ' onewire reset signal
       ow_write(PORTA,IBUTTPIN,$CC)                 ' write skip read ROM
       ow_write(PORTA,IBUTTPIN,$0F)                 ' write to Scratch pad
       ow_write(PORTA,IBUTTPIN,Lo(location))        ' write location lower byte
       ow_write(PORTA,IBUTTPIN,Hi(location))        ' write location higher byte
       ow_write(PORTA,IBUTTPIN,Highest( currentTime ))   ' write time (highest byte)
       ow_write(PORTA,IBUTTPIN,Higher( currentTime ))    ' write time (evem more higher byte)
       ow_write(PORTA,IBUTTPIN,Hi( currentTime ))        ' write time (higher byte)
       ow_write(PORTA,IBUTTPIN,Lo( currentTime ))        ' write time (lower byte)

       delay_us(200)                       'delay, needed to work


       ow_reset(PORTA,IBUTTPIN)            ' onewire reset signal
       ow_write(PORTA,IBUTTPIN,$CC)        ' skip ROM
       ow_write(PORTA,IBUTTPIN,$AA)        ' read scratchpad
       Ow_Read_Serial(PORTA,IBUTTPIN,js,7)
       delay_us(200)

       ' check if scratchpad is correct
       if (js[0]=Lo(location)) and (js[1]=Hi(location)) then

           ow_reset(PORTA,IBUTTPIN)             ' onewire reset signal
           ow_write(PORTA,IBUTTPIN,$CC)         ' skip ROM
           ow_write(PORTA,IBUTTPIN,$55)         ' copy to memory
           ow_write(PORTA,IBUTTPIN,js[0])       ' write location
           ow_write(PORTA,IBUTTPIN,js[1])       ' - I I -
           ow_write(PORTA,IBUTTPIN,js[2])       ' write extra control byte
           delay_us(200)

           ow_reset(PORTA,IBUTTPIN)             ' onewire reset signal
           ow_write(PORTA,IBUTTPIN,$CC)         ' skip ROM
           ow_write(PORTA,IBUTTPIN,$F0)         ' read from memory
           ow_write(PORTA,IBUTTPIN,Lo(location))' set location from where to read
           ow_write(PORTA,IBUTTPIN,Hi(location))
           delay_us(100)

           Ow_Read_Serial(PORTA,IBUTTPIN,js,4)  ' read 4 bytes of data from memory

           if ((js[3] = Lo(currentTime)) and (js[2] = Hi (currentTime)) and
               (js[1] = Higher(currentTime)) and (js[0] = Highest (currentTime))) then
              firstWriteOK=1
           end if
      end if

       ' loop until time is correctly written
      loop until ( firstWriteOK=1 ) or  (currentTime+2<sec)

      wasConnected=firstWriteOK
    end if
end sub



' time interrupt for 16F628
' interrupt occurs at 1/2 sec intervals
sub procedure interrupt
   inc(counter)         ' Increment value of counter on every interrupt
   pir1.TMR1IF = 0      ' Clear TMR1IF

   if counter = 2 then  ' if counter is 2, that is 1sec
       inc(sec)
       counter = 0
       PORTA.REDLED = LEDOFF

       if(clockset > 1) then  ' flash red LED on the minute
         if (sec mod 60 = 0) then
             PORTA.REDLED = LEDON
             dec(clockSet)
         end if
       end if
       
       if ((sec + idBox) mod 300 = 0) then  ' quiet beep every 5 mins
          PORTA.BUZZ=1
          delay_ms(10)  ' 10  works best
          PORTA.BUZZ=0
       end if

       if (clockSet = 0) then ' warning that clock is not set
          PORTA.REDLED = LEDON
          delay_ms(50)
          PORTA.REDLED = LEDOFF
          PORTA.BUZZ=1
          delay_ms(100)
          PORTA.BUZZ=0
       end if
    end if
end sub


main:



   TRISA =   0                     ' porta is output (except RA1)
   PORTA =   0                     ' initialize porta
   
   TRISB =   $FF                   ' portb is input
   OPTION_REG.NOT_RBPU=0           ' enable individual pull-up
   
   CMCON = 7                       ' Disable Comparators

   counter = 0             ' Initialize counter
   sec=0
   tim=0
   clockSet = 0
   T1CON = $31             ' start the timer
   PIR1.TMR1IF = 0         ' clear TMR1IF
   PIE1  =   1             ' enable TMR1 interrupts
   INTCON = $C0            ' Enable global TMR interrupt

   ' read DIP for idBox
    idbox =  PORTB
    idBox =  idBox xor $FF  ' invert bits
    idBoxLoc=idBox*4
    
    OPTION_REG.NOT_RBPU=1           ' disable individual pull-up

   _loop:



       ' first, we read iButton if present

       ow_reset(PORTA,IBUTTPIN)            ' onewire reset signal
       ow_write(PORTA,IBUTTPIN,$33)        ' read iButton - read ROM
       Ow_Read_Serial(PORTA,IBUTTPIN, js,8) ' read 8 bytes of Dallas iButton

       crcTest=0
         for i=0 to 6
           ByteCRC(crcTest,js[i])
         next i

       ' check if iButton present
       if (((js[0] and js[1] and js[3] and js[4] and js[5] and js[6] and js[7])<>$FF)
       and  (crcTest <> $FF) and (crcTest<>$00) and crcTest=js[7]) then   ' iButton is not present

          if wasConnected=0 then                     ' ibutton present, check if multiple writing

            if js[0]=$24 then
                 readTimeFromButton()                    ' read time from button
             else
                writeTimeToButton(idBoxLoc)              ' normal button - write  current time to button
            end if

          end if

          ' ibutton is not present
          else
          ' it was already wasConnected and now is disconnected (wasConnected=0)
          wasConnected=0

       end if

       if wasConnected=1 then
           ' flash red led
          PORTA.REDLED=LEDON
          delay_ms(30)
          PORTA.REDLED=LEDOFF
          delay_ms(30)
          PORTA.BUZZ=1
          delay_ms(200)
          PORTA.BUZZ=0
          delay_ms(200)
       end if
   goto _loop
end.