I made a 'custom' PCB that integrates the Arduino Nano http://arduino.cc/en/uploads/Main/ArduinoNano30Schematic.pdf running at 3.3V and 8Mhz and the temperature sensor DS18B20. I am downloading the code using the AVRISP. Due I was not able to download the bootloader successfully to my board.
So, using the Dallas Temperature library and the OneWire I just want to see what is the current temperature getting by the sensor. The problem is that I am getting 'TI: -127' on the Serial Monitor. I am not sure why is this happening. So, I physically connected a cable to the output pin on the PCB to another Arduino which is the Arduino Duemilanove which came already assembled, and I saw the output as 'TI: 24.67', which is the output I expected.
I used the same schematic from the website and I just added the temperature sensor, but removed the FTDI but not the pins to interface the SparkFun FTDI to be see the output from the micro.