Does anybody knows how to interprete raw value of temperature data of L3G4200D gyroscope?
Indeed, when you read the 26h register, you get a raw 8-bit value but i don’t know how to get a real value of temperature in Celsius.
Thank you very much!!
PS the only thing i know:
“The L3G4200D is provided with an internal temperature sensor that is suitable for delta
temperature measurement. Temperature data are generated with a frequency of 1 Hz and
are stored inside the OUT_TEMP register in two’s complement format, with a sensitivity if -1
LSB/°C.”
The datasheet doesn’t seem to provide much information about using the temperature sensor, but my understanding is that it is not intended to give you an absolute measurement of the ambient temperature. Instead, I think it is supposed to allow you to detect relative changes in the temperature of the chip in case you want to try compensating the gyro readings for temperature.
I just tried reading the temperature output from an L3G4200D and I initially got a value of 12. If I put my finger near the chip and the reading decreases to 8, since the datasheet specifies on page 11 that the temperature sensor’s output represents a change of -1°C/digit (the same as the -1 LSB/°C you mentioned; LSB stands for least significant digit), I know that the temperature of the chip has increased by 4°C.
You might be able to correlate the numbers from the temperature sensor with actual absolute temperatures - for example, you might decide that a value of 12 means 25°C - but the relationship might vary among different chips and I don’t expect it to be very accurate.
