int ow_readBit(int pin) {
int result;

PinSetBit(pin, LATCLR); // drive pin low
   uSec(3);
PinSetBit(pin, TRISSET); // set as input
   PinSetBit(pin, LATSET); // release the bus
   uSec(10);
   result = PinRead(pin); // read pin
PinSetBit(pin, TRISCLR); // set as output
uSec(53); // wait 56uSec
return result;
}

'DS18x20 test code by TassyJim
 DIM INTEGER PinNbr = 24 ' 22
 DIM FLOAT tem
 PRINT
 PRINT "Family name: ";FamilyName$(PinNbr)
 PRINT "Rom Code:    ";getRomCode$(PinNbr)
 PRINT "Shifted :    ";bitshift$(getRomCode$(PinNbr))
 PRINT "ScratchPad:  ";getScratchpad$(PinNbr)
 PRINT "Shifted :    ";bitshift$(getScratchpad$(PinNbr))
 
 IF powerMode(PinNbr) THEN
   PRINT "Power mode   External"
 ELSE
   PRINT "Power mode   Parasitic"
 ENDIF
 
 PRINT
 tem =TEMPR(PinNbr)
 PRINT "temperature= "; tem
 PRINT "scratchpad   ";HEX$(tem*16-256,2);" 01..."
 FOR n = 0 TO 3
   PRINT
   TIMER = 0
   PRINT "Temperature: ";getTemp(PinNbr,n);" ";TIMER;"mS,";n+9;" bit "
   PRINT "ScratchPad:  ";getScratchpad$(PinNbr)
   PRINT "Shifted :    ";bitshift$(getScratchpad$(PinNbr))
   
 NEXT n
 
END
 
FUNCTION bitshift$(bits$)
 LOCAL INTEGER n
 bits$= bt$+bits$
 bits$ = LEFT$(bits$,64)
 FOR n = 0 TO 7
   bitshift$ = bitshift$ +HEX$(VAL("&h"+MID$(bits$,n*3+1,2))/2,2)+" "
 NEXT n
END FUNCTION
 
FUNCTION getRomCode$(PinNbr AS INTEGER)
' get ROM Code - useful if you want more than 1 device on wire
 LOCAL INTEGER a1,a2,a3,a4,a5,a6,a7,a8
 ONEWIRE WRITE PinNbr,1,1,&h33 'read ROM code
 ONEWIRE READ PinNbr,2,8,a1,a2,a3,a4,a5,a6,a7,a8
 getRomCode$ = HEX$(a1,2)+" "+HEX$(a2,2)+" "+HEX$(a3,2)+" "+HEX$(a4,2)+" "+HEX$(a5,2)+" "+HEX$(a6,2)+" "+HEX$(a7,2)+" "+HEX$(a8,2)
END FUNCTION
 
FUNCTION getScratchpad$(PinNbr AS INTEGER, style AS INTEGER)
 LOCAL INTEGER a1,a2,a3,a4,a5,a6,a7,a8,a9
 ONEWIRE WRITE PinNbr,1,2,&hcc,&hbe
 ONEWIRE READ PinNbr,2,9,a1,a2,a3,a4,a5,a6,a7,a8,a9
 getScratchpad$ = HEX$(a1,2)+" "+HEX$(a2,2)+" "+HEX$(a3,2)+" "+HEX$(a4,2)+" "+HEX$(a5,2)+" "+HEX$(a6,2)+" "+HEX$(a7,2)+" "+HEX$(a8,2)
END FUNCTION
 
FUNCTION powerMode(PinNbr AS INTEGER) AS INTEGER
' check whether power external (1) or parasitic (0)
 ONEWIRE RESET PinNbr
 ONEWIRE WRITE PinNbr, 1,2,&hcc, &hb4
 ONEWIRE READ PinNbr,4,1,powerMode
END FUNCTION
 
FUNCTION getFamily(PinNbr AS INTEGER) AS INTEGER
 getFamily = VAL("&h"+LEFT$(getRomCode$(PinNbr),2))
END FUNCTION
 
FUNCTION FamilyName$(PinNbr AS INTEGER)
 LOCAL INTEGER fn
 fn = getFamily(PinNbr) AND &h7F
 SELECT CASE fn
   CASE 16
     FamilyName$ = "DS1820/DS18S20"
   CASE 34
     FamilyName$ = "DS18S22"
   CASE 40
     FamilyName$ = "DS18B20"
   CASE 32 ' 16 * 2
     FamilyName$ = "*** DS1820/DS18S20"
   CASE 68 ' 34 * 2
     FamilyName$ = "*** DS18S22"
   CASE 80, 81 ' 40 * 2
     FamilyName$ = "*** DS18B20"
   CASE ELSE
     FamilyName$ = "Unknown"
 END SELECT
END FUNCTION
 
FUNCTION setResolution(PinNbr AS INTEGER,r AS INTEGER)
 IF r < 0 THEN r = 0
 IF r > 3 THEN r = 3
 ONEWIRE WRITE PinNbr, 1,5,&hcc, &h4E, &h00,&h00,r*32
END FUNCTION
 
FUNCTION getTemp(PinNbr AS INTEGER,prec AS INTEGER) AS FLOAT
 LOCAL INTEGER fn, t, a1,a2,a3,a4,a5,a6,a7,a8,a9
 LOCAL FLOAT Value
 fn = getFamily(PinNbr) AND &h7F
'power = powerMode(PinNbr)
 power = 0 ' we have disabled the external/parasitic check and stick to parasitic timing
 t = setresolution(PinNbr,prec)
 
'read external when b goes high, for parasitic just wait
 IF power = 0 THEN
   ONEWIRE WRITE PinNbr, 9, 2, &hcc, &h44      ' start conversion
   PAUSE (100 << prec) ' pause time varies depending on resolution
 ELSE
   ONEWIRE WRITE PinNbr, 1, 2, &hcc, &h44      ' start conversion
   t = TIMER
   DO
     IF TIMER - t > 1000 THEN
       Value = 1000
       EXIT DO
     ENDIF
     ONEWIRE READ PinNbr, 4 , 1 , b            ' conversion done?
   LOOP UNTIL b = 1
 ENDIF
 
 
 ONEWIRE WRITE PinNbr,1,2,&hcc,&hbe
 ONEWIRE READ PinNbr,2,9,a1,a2,a3,a4,a5,a6,a7,a8,a9
 
 SELECT CASE fn
     
   CASE 16, 32'DS18S20 or DS1820
     
     IF a2 AND &h80 THEN       'if MSB of a2=1 then negative
'Read 12bit resolution and adjust
'truncate 0.5deg value (or use integer division \)
       a1 = a1 AND &hFE
       a1=a1 / 2                   'make whole degrees
'add compensation values read from scratchpad
       a1=a1*16                  'make lsb 1/16 degree
       a1 = a1 -4 +(16 - a7)    'add 12 bit value
'take 2s complement
       a1 = (a1 XOR &hFF) + 1
       Value = -a1/16                'make decimal value in degrees
     ELSE                              'positive temp
       Value = a1 / 2                '9bit value
'Read 12bit resolution and adjust
       a1 = a1 AND &hFE      'truncate 0.5deg(or use integer division \)
       Value = a1/2- 0.25 + (16 - a7) /16   '12 bit value
     ENDIF
   CASE 34, 40, 68, 80 ' DS18S22 or DS18B20
     IF (a2 AND &b1000) THEN       'negative temp
'make 2s complement (1s complement+1)
       a2 = (a2 XOR &hFF)
       a1 = (a1 XOR &hFF)+1
       IF a1=1 THEN a2=a2+1        'add the carry if required
       Value = -((a2 AND &b111) * 256 + a1) / 16
     ELSE                          'positive temp
       Value = ((a2 AND &b111) * 256 + a1) / 16
     ENDIF
   CASE ELSE
'Value = 1000 we have defeated the checks to see whats happening
     Value = ((a2 AND &b111) * 256 + a1) / 16
 END SELECT
'ENDIF
 getTemp= Value
END FUNCTION

open "com1:115200, 256, SerInt, 4" As #1 ' interrupt triggered with 4 characters

SetTick 1000,myint
t=Timer
Do
SetTick pause,myint
Pause 500
SetTick resume,myint
Pause 1000
Loop
Sub myint
Print Timer-t
t=Timer
End Sub

SetTick 1000,myint,4
t=Timer
Do
SetTick pause,myint,4
Pause 500
SetTick resume,myint,4
Pause 1000
Loop
Sub myint
Print Timer-t
t=Timer
End Sub

' serialClient.bas acts on serial messages
' if first character is "!", text data is to be returned, CR terminate
'   otherwise, single command is to be run with "EXECUTE"
OPTION AUTORUN ON
dim integer msg(3)
dim string cmd
pause 2000
print "Picomite SerialClient starting"
SetPin 22,21,com1 ' setpin 21,uart0tx:SetPin 22,uart0rx
open "com1:115200, 256, SerInt, 4" As #1 ' interrupt triggered with 4 characters

DO ' the program loops forever
WATCHDOG 2000 ' this will recover from errors
LOOP

SUB SerInt ' received a message
msg(0)=asc(input$(1,#1))
if chr$(msg(0)) <> "!" then
  pause 30 ' allow all characters in command to arrive
  line input #1,cmd
  cmd=chr$(msg(0))+cmd ' input$(255, #1)
  print cmd
  EXECUTE cmd
else ' function call will return data
  msg(0)=asc(input$(1,#1)): msg(1)=asc(input$(1,#1)): msg(2)=asc(input$(1,#1))
  print msg(0);" ";msg(1);" ";msg(2);" "
  if msg(0) = 3 then ' the command must be 3
    if msg(2) = 10 then ' DS18B20
'        s$ = mid$(str$(tempr(pin(msg(1)),3,3) + Space$(12),1,12) ' get the temperature
      s$ = str$(tempr(pin(msg(1))),3,3) ' get the input on the I/O pin
      print s$
    else ' value of DIN, AIN, CIN, FIN, PIN pin
'        s$ = mid$(str$(pin(msg(1))) + Space$(12),1,12) ' get the input on the I/O pin
      s$ = str$(pin(msg(1))) ' get the input on the I/O pin
  print "pin(";msg(1);"): "+s$
    endif
    print #1,s$
  ENDIF
ENDIF
do while loc(1)>0: cmd=input$(255,#1): loop ' flush the input buffer
END SUB ' return from the interrupt

> option reset                                                    
> OPTION DISPLAY 49, 100
Error : Invalid Option
> OPTION DISPLAY 49    
Error : Invalid Option
>