Understanding more about SMC Keys

I thought of writing this up , to explain on what I’ve been doing or up to. Lately , a few folks (yeah great developers of OSX86) and I are working on mapping SMC keys to understand more on how SMC Controller works on Mac. This could be useful for Linux community and especially for hackint0sh. The reason is simple , as we all do know that Intel Macs do use SMC Controller to get Temperature Reading for HDD , Processor , GPU and other stuff.  This way we could obtain data from our Electronic Controller or Sensors and send it to FakeSMC to be given to the OS. So that applications such as iStat would report the correct temperature.
Anyhow , I gotta thank the iStat Team for this. I’ve been collecting this data from iStat Pro. Basically this is how iStat Pro functions. It gets the values from SMC Keys and then displays it to the OS. Thats how Temperature keys are retrieved from the OS . Anyhow , here are some keys (again you can use FakeSMC , fill it up with fake Information to get a dummy reading). Obviously it could be a point of interest of those who are looking to further FakeSMC.
TC0H , TC0D – Keys which are related to CPU Temperature (FakeSMC 2.5 has this already)
TG0D – GPU Diode Temperature for ( nVidia Video cards) (not sure for ATI cards as I dont have any data from a MacPro or Desktop Macs yet)
TG0P – GPU Temperature for Intel onboard Video cards (only X3100 it seems , GMA 950 lacks of this key)
TG0H/TG1H – GPU Heatsink (possible the fan speed of the GPU itself)  (again I am not sure about this key , a few macs do seem to have this)
TA0P – Ambient Light Sensor (Intensity of the Light which I believe is measured in (  W m^-2) (Not sure , needs more data)
Now some infos for the fan
FNum – Number of fans installed on the System
F<integer>Ac = Fan # x (where x = 1 , 2 , 3 …?) . It seems that the SMC keys can hold up to ? number of fans. It can handle that much.  (the speeds are in RPM , no not in radian/sec)
These is all that I can make sense out of it. There are more then that, however none of the real macs (or maybe they do) have all the stuff that it inside the source code. These keys can be useful for our Hackint0shes. if you wanna dig deeper then check this out

3 thoughts to “Understanding more about SMC Keys”

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