I am sensitive to fan noise and have been using Shimodax's tpfancontrol and NHC fan control on an A31 without clue which temp sensor means what. So, I finally had to take my laptop apart, take freeze spray to the motherboard and find (fairly exactly) all the temperature sensors, so we know which is which.
Here they are, and their corresponding EC addresses:
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Label Address Typical Temp Notes
CPU 0x78 36-40 CPU for sure
BAT1a 0x79 32 Battery (main) - heats up when laptop on battery power, cool when AC
PWR 0x7a 40-46 Power diodes - sensor left of CPU, top side
BAT2a 0x7b (probably) Ultrabay 2000 Battery (main?)
BUS 0x7c 48 Northbridge - sensor below and left of Northbridge, bottom of MB
PCM 0x7d 25 PCM/ambient - near VGA 9pin plug (LM75 single temp sensor chip); seems always lowest temp (room temp)
BAT1b 0x7e 31 Battery (ambient) - 0 when battery removed, but doesn't heat up under battery load
BAT2b 0x7f (probably) Ultrabay 2000 battery (ambient?)
- 0xc0 0 none of these (below) have any values
- 0xc1 0 "
- 0xc2 0 "
- 0xc3 0 "
Now that the sensor labels are right, I'll upload an NHC control script I have been using, which allows fan control inside NHC.
Hope this helps. One curious fact is that the thermal sensor chips appear to have more or less total ports than the temps identified depending on whether you assume batteries are measured by them or not (CPU tells its own?). So if I didn't miscount it's possible that some temperatures may be hidden elsewhere in the EC memory.. Anyone any ideas?
Milos