DS18B20 an PIC12F1572 liefert nur 255,255

program DS18B20_Test

dim LED as sbit at RA4_Bit

dim OneWire as sbit at RA5_Bit

sub procedure InitHardware

    PORTA = %00000000         'Reset all IO bits

    TRISA  = %00101010        'Select inputs/outputs

    SLRCONA = %00000000       'Disable slewrate limit

    'TRISA.0  = 0             'RA0 = Output = TX

    'TRISA.1  = 1             'RA1 = Input = RX

    'TRISA.2  = 0             'RA2 = Output = Reserved

    'TRISA.3  = 1             'RA3 = Input = Reserved

    'TRISA.4  = 0             'RA4 = Output = LED

    'TRISA.5  = 1             'RA5 = Input = 1 Wire

    'TRISA.6  = 0             'Not implemented

    'TRISA.7  = 0             'Not implemented

    ANSELA  = %00000000       'All pins are digital

end sub

sub procedure ReadTemperature

    dim temp as byte

    Ow_Reset(PortA, 5)        'Reset Onewire

    Ow_Write(PortA, 5, 0xCC)  'Send SKIP_ROM

    Ow_Write(PortA, 5, 0x44)  'Send CONVERT_T

    Delay_ms(750)             'Wait 750ms for conversion end

    Ow_Reset(PortA, 5)        'Reset Onewire

    Ow_Write(PortA, 5, 0xCC)  'Send SKIP_ROM

    Ow_Write(PortA, 5, 0xBE)  'Send READ_SCRATCHPAD

    temp = Ow_Read(PortA, 5)  'Read first byte

    UART1_Write(temp)         'Write to UART

    temp = Ow_Read(PortA, 5)  'Read second byte

    UART1_Write(temp)         'Write to UART

end sub

main:

     InitHardware             'Setup the hardware

     UART1_Init(19200)        'Setup the UART

     while 1                  'Mainloop

           clrwdt             'Clear watchdog timer

           LED = LED xor 1    'Toggle LED

           delay_ms(250)      'Wait 1 second (~750ms from DS18B20)

           ReadTemperature    'Read temperature

     wend

end.