A logic IC with no IC number?

Question

Thank you for answering my question.
My problem is that I have a Logic IC that it's name and IC number is fully cleaned & I did'nt know any think about it.
By analysing the circuit that this IC used in it, I had determined its VCC & GND but I need to determine it fully.
I want only a way for determinig its pin (input or output).
Then I can find its truth table for every output by letting different input valuations to it and processing its response by an AVR.

Can you help me?
please place your mail here or mail me your answer if you want, then I can explain you more details of problem and ...

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Answer 1

The answer is PATIENCE!
Since you already know where is +V and 0V, you are already half way there.
Now take a volt meter and connect it to any of the other legs and +V.
Then take a probe which has 220 Ohm (or so) to 0V. Basically, you want to make inputs low and see whether anything happens to the other pin, but you don't want to use 0V without the resistor, because who knows, you might test an output and not an input.
Now you go through pin-by-pin 12 X 12 = 144 times!
But how are you going to find out gates with several inputs,
or IC's which are not a gate at all??!
There must be a better way to find out what that IC is supposed to be.....
Where did you get that IC from? Is there a circuit diagram or photo of the whole thing?
Unless you have to repair the "whole thing", the effort finding out what that IC is (amongts the millions on the market) is totally uneconomical.

Answer 2

That's almost impossible. If it's a latch or a flip flop or a memory chip it just doesn't respond to levels. It requires timing relations between pins to be met.

Answer 3

To make a reliable level triggered sync counter you need to use Master/Slave JK flip flops such as the 7471 or 7472.