DS18S20 & Parasite Power

I've tried using the parasite power option and can not seem to get it to work at all. Is there something I'm missing from my code? It works fine using three wire but not two.

Code:

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read_temp:
    owout portb.7,1,[$CC, $44]                  ' Send start temperature conversion
    owout portb.7,1,[$CC, $BE]                  ' Send read scratchpad command
    for x = 0 to 8                              ' Process all 9 bytes
    owin portb.7,0,[i]                          ' Read the scratch pad
    dq[x] = i                                  ' Place read byte into the array
    next x                                      ' Do again until all 9 bytes are processed
    temp.Byte0 = dq[0] : temp.byte1 = dq[1]    ' Store bytes 0 and 1 in the temp word variable
    if temp.8 = 1 then                          ' If bit8 of temperature is set then its negative               
    sign = "-"                                ' Indicate temperature is NEGATIVE
    temp.lowbyte = temp.lowbyte ^ 255                ' Reverse the bits of the lowbyte of TEMP
    sign = " "                                ' Indicate temperature is POSITIVE
        endif
        half = temp.0
    temp = ((temp.lowbyte) >> 1) * 10              ' Shift the lowbyte of the result right 1 place
    temp = temp + (half * 5)                        ' Strip off bit 0 (0.5 degree) and add it to DEC

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I figured it out. I wasn't sure if would work with the ONIN/OWOUT commands or not but it appears it works just fine. I'm now running a sensor 25ft away on a Cat5 computer cable. All I was missing was the part where I had to drive the Dallas chip to the rail for a period of 600ms.

Code:

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read_temp:
    owout portb.7,1,[$CC, $44]                  ' Send start temperature conversion
    low portb.6                                ' Turn on transistor connected to rail
    pause 600                                  ' Allow enough time for Tconv
    high portb.6                                ' Turn off transistor
    owout portb.7,1,[$CC, $BE]                  ' Send read scratchpad command
    for x = 0 to 8                              ' Process all 9 bytes
    owin portb.7,0,[i]                          ' Read the scratch pad
    dq[x] = i                                  ' Place read byte into the array
    next x                                      ' Do again until all 9 bytes are processed
    temp.Byte0 = dq[0] : temp.byte1 = dq[1]    ' Store bytes 0 and 1 in the temp word variable
    if temp.8 = 1 then                          ' If bit8 of temperature is set then its negative               
    sign = "-"                                ' Indicate temperature is NEGATIVE
    temp.lowbyte = temp.lowbyte ^ 255                ' Reverse the bits of the lowbyte of TEMP
    sign = " "                                ' Indicate temperature is POSITIVE
        endif
        half = temp.0
    temp = ((temp.lowbyte) >> 1) * 10              ' Shift the lowbyte of the result right 1 place
    temp = temp + (half * 5)                        ' Strip off bit 0 (0.5 degree) and add it to DEC

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