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How can i find pins of an unknown ic ? with or without an oscilloscope Answered

i've found a touchpad (model 810511-0901)  that i would like to use with my arduino , but i can't find the datasheet of the ic . i've googled for a guide that explain how to sniff the data pins but nope :(


Is this what you have? You could start with the connector pins and find the pos and neg pins, the rest should be data. Alternately, you could contact Compal at one of the three places listed on their site. Lastly, you do realize that you will have to research how this unit works and write a driver for it, don't you? It won't be a plug and play thing similar to other input types where there "may" be library or routine already written for that particular device. Since there are no real links to this thing, that might be extremely difficult to do.

Good luck on your mission.


i hope it uses a ps2 interface, everything whould be much simpler . the question is : hou can i find the positive and negative ? , i mean avoiding the risk of current invertion
thank you for your reply

To find the power leads, you'll need to know which one is VCC on the IC and which one is GND. Look it up if you can. Alternately, look to see which one goes to the ground plane around the outside of the PCB. That would be GND, obviously. There seems to be a few chip capacitors on there, maybe one that goes to the ground plane is connected to VCC. The rest, I cannot tell you much about without some sort of info on the IC and board itself.

Good luck,

Touchpad from what ?


It is possible to reverse engineer the circuit if you can get the data sheet on the IC. If you don't have that information or the IC's markings are not there then it becomes nearly impossible to do it. You need the right lab equipment and know how to pull it off.

Not at all easy BUT have you tried one of the free PC scopes that use the sound card input to "sniff" around.