Accessing LPC signals on the LPC Debug Connector

[Niranjan]

I am doing laboratory course on computer hardware on X220 Lenovo laptop. For the ACPI/Embedded Controller experiment, I connected the Logic Analyzer(LA) to the Low Pin Count (LPC) Debugger Connector pins on the motherboard. I could see the LPC bus signals and interpret them. After a few days of experiment I do not see any LPC signals on the LA, however the laptop is working properly with Windows 7 running fine.

What may have happened? How do I revert back to the LPC signal sampling from the motherboard? Is it an issue of the TPM (Trusted Platform Module) on the motherboard?

Thanks,
Niranjan

[axur-delmeria]

The first thing I would do is look for the schematics of the X220.
Then, I'd inspect the components around the LPC debug connector to see if any of them have failed.

[Niranjan]

The first thing I would do is look for the schematics of the X220.
Then, I'd inspect the components around the LPC debug connector to see if any of them have failed.

Thanks very much. I did look into the schematics of the X220. But, I am unable to see why the LPC lines are being shut off from any information on this page.

Niranjan