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I have salvaged this TrackPoint from a lenovo laptop keyboard. Unfortunately I don't know the exact model, but I don't think it's older than say 6 years. I would like to connect this to my PC via an Arduino, mbed, teensy or direct PS/2 and use it as a mouse.

Here's my question: What's the pinout of this device, or how can I find out what it is (without harming the device)?

I've found numerous pinouts online, but none of the pictures/descriptions that have pinouts appear to match the PDB layout of my TrackPoint, because they typically have the VCC and GND rails close together, whereas mine appear to be on pins 1 & 5, since those lines are the thickest in the flexible connector. Furthermore, my TrackPoint has 8 pins, many of the ones found around the web have 10. I don't have the keyboard or laptop anymore, so I can't exactly use a multimeter to measure voltages in a working system.

Here are some pictures, I'll add links to the sources I've found so far below.

TrackPoint front

TrackPoint back

Markings:

PCB front:

  • LVC9
  • 142399H
  • Rev. A

PCB back:

  • 1046
  • CPCP GG
  • 94V-O
  • C 9U

The bigger chip (32 pins):

  • PTPM754DR
  • CT2926 10
  • D104IC
  • 0 B

What I've found so far..

Any ideas?

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  • \$\begingroup\$ This Chip has a datasheet, TPM754 - link its a phillips IC that has IBM licensed embedded TrackPoint microcode . It even has a convenient suggested application schematic and pinout, WOW! \$\endgroup\$ – crasic Feb 19 '16 at 1:01
  • \$\begingroup\$ Note that's for the TPM754DB, not DR. The TPM754DB has 28 rather than 32 pins. \$\endgroup\$ – m01 Feb 19 '16 at 7:36
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I managed to completely reverse the pins of this module:

Considering your first picture above, being the rightmost pin the number 1 (near the white dot), I've got, from right to left:

  1. Mousebutton0
  2. Mousebutton1
  3. Mousebutton2
  4. 5V
  5. Reset
  6. Clock
  7. Data
  8. Ground

Update: I confirm it works finally as described above. I'm using tmk firmware and tried on teensy2.0 and pro micro.

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