>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>On Behalf Of XYZ XYZ
>Sent: 17 June 2007 11:19
>To: piclist@mit.edu
>Subject: [PIC] microchip c18 - 1wire lib 
>
>
>int gettemp(void)
>{
>   int buff[9], sensor, n;
>   int temperature;
>   sensor = 0;
>
>      _1w_out_byte(0xcc, sensor);  // skip ROM
>
>      _1w_out_byte(0x44, sensor);  // perform temperature conversion
>      _1w_strong_pull_up(sensor);
>
>      _1w_init(sensor);
>      _1w_out_byte(0xcc, sensor);  // skip ROM
>
>      _1w_out_byte(0xbe, sensor);  // read the result
>
>      for (n=0; n<9; n++)
>      {
>         buff[n]=_1w_in_byte(sensor);
>      }
>
>
>	temperature = buff[0]>>1;  // temperature without LSB (0.5C)
>
>  return temperature;
>}


You must send a reset pulse before trying to send any commands.  This is clearly described in the DS18B20 datasheet under the heading "Transaction Sequence" on page 10.

Regards

Mike

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