I am posting this question on behalf of our hardware engineer James. I am the software engineer developing the BIOS for a new Atom embedded design.
Our problem is that the Atom CPU asserts the ThermTrip# signal shortly after initialization. This occurs after the chip-set microcode has started execution, but before the Atom CPU fetches the first instruction.
The board is a custom design based on the Intel Swift Current 2 reference design. Here are the details of the hardware.
We have the following SoftStraps settings in microcode.
Here is a bit more detailed description of the problem from our hardware engineer, James. The System Controller Hub starts loading the microcode but stops at ucode address D7FF. Then H_CPUPWRGD from the SCH goes true and ThermTrip# from the processor goes true at the same time. This causes a catastrophic shutdown. I think that the thermtrip# is completely erroneous since the processor is still cold and has been powered on for less than a second. Voltages look good and proper power sequencing has been observed. What could be causing the ThermTrip# ?
Any help is greatly appreciated.
I assume ThermTrip# signal is between CPU & IMVP chip
ThermTrip# pin is bidirectional & it may be asserted either by processor or IMVP ic.
In my case ThermTrip# pin was false triggered by IMVP IC which was not properly configured for required temperature.
Impact of ThermTrip# assertion cases TM2 to be enabled & processor gets throttled & alway operated at Low Frequency Mode.
I hope the above information be helpful.