Lexmark Pointer Device (FSR) signal mapping?

[SunshineRag_DT]

As mentioned in a previous post I have a Lexmark M13 which uses a Force Sensitive Resistor (FSR - Not a Star Wars Jedi skill!) technology vs the IBM Trackpoint II strain gauge devices. There is alot of a documentation on using other Trackpoint II devices but I can find very little on the Lexmark technology. Has anyone done a signal trace of these devices?

Here is a picture of the pointer module in my keyboard, and the traces of the connector that go into the controller. It appears to bring 5 signals off the pointer module and I am just trying to see if anyone has mapped these before? I am wondering if these are encoded signals or some sort of analog input that is decoded on the controller as it definitely looks like there is a need for processing on the controller.


Lexmark FSR Pointer module:

Lexmark_Pointing_Stick.jpg (1.87 MiB) Viewed 2717 times

FSR Module Connection cable:

Lexmark_Connector_Cropped.jpg (46.58 KiB) Viewed 2717 times

Lexmark M13 Control Board:

20230123_100231 - Copy.jpg (793.05 KiB) Viewed 2717 times

Production Plate and Part No:

Lexmark_Part_Number.jpg (1.83 MiB) Viewed 2717 times