Test different IC with Microcontroller

[conanhaha]

I am constructing an IC tester with micro-controller.
The IC i test for now is op-amp and 555 Timer, and later may be Digital Logic gate IC.
How should I synchronize all the different IC test by using micro-controller?
For example, different IC pin got different Vcc, GND, different input and so on.
What should I do to test these different IC with micro-controller?

Besides that, I am using window comparator for the testing output, the output voltage is 13-14V and 0V. What should I use to step down the voltage to 5V to fit in micro-controller? As I heard from some people may use High to Low shifter, is it ok?

 

[bobcat1]

Hi

In order to do that you will need to use a separate DAC (digital to analog converter) on any pin of IC you are trying to emulate and an ADC on any pin you are trying to test - this will make a complicated design....

If you are still in it... then Analog Device & MAXIM produce multi channel DAC IC
it is a bit costly device but you can try to ask for a sample.


All the best

BObi

The microcontroller specialist

 

[conanhaha]

Hi~
Is that any other ideas to test all the different IC with Micro-controller?
It is because my project budget is limited and high cost project should not be implemented.
My lecturer concern is to test more ICs rather than the characteristic of single IC.
All ICs that to be test is put in the same IC socket.
So is that any other easier way to use Micro-controller to synchronize testing of a few kind of ICs?

 

[yego]

If you intend to test ICs with various supply voltages, then you definitely need either DACs or some other circuits supplying needed voltages to tested ICs.
Also, in such a case you'll need suitable level shifters to connect your IC outputs to your uC.
The best you can do is to decide to use ICs supplied with just one voltage, say 5V.
This would simplify your design greatly.
Once your HW is ready you'll need to define test vectors for your DUTs and response signatures your uC will compare against real responses from tested ICs.

I saw once a design of such tester for TTL devices.
I guess it was published by Steve Ciarcia in the Byte magazine around middle 80's.
Perhaps there are pdfs still available...

Besides, if you decide to test just TTLs, the design is not this hard
All you need is ample memory to store test vectors, and of course a simple 8-bit uC with sufficient number of I/O pins.

 

[conanhaha]

Hi~
Thanks for reply~
The part i feel hard is I need to test different kind of IC which consist of Analog IC and Digital IC.
At first stage I need to design for op-amp test.
To implement such test I had design a window comparator and compare the voltage is within the range or not, and with only low and high output (lv shifter to 5V) back to uC.
After this analog op-amp test, I need to further enhance it to test various other IC, such as Digital Logic Gate IC ( 7408, 7486, 7432 ), Flip Flop, 555 Timer and so on.

The part i not understand is how do I test these different types of IC together in 1 IC tester?
This is confusing me

 

[yego]

You certainly must know what IC types you are going to test in order to be able to build test vectors for them. Once you know it, you must decide what parameters you are going to test. This may decide on your HW design.
For high voltage you need interface circuits which can apply desired vectors and feed back the response to your uC for comparison.
If you require testing dynamic characteristics, your design will be much more demanding than just to measure static ones.
First things first.
Decide what and how you are going to test. Thats your starting point.

 

[conanhaha]

Hi~ Thanks again for reply.
I will try to decide what is the second IC that i gonna test after I finish test on 741 op-amp.
For now I just construct some circuit to test the analog IC test of op-amp.
After this I will do some research on how to test those 7408, 7486, 7432 IC and so on.
This is the example circuit that i construct to test op-amp.
If the output voltage of op-amp is within the range of 0-5V, then the output of window comparator will held low.
If the output voltage of op-amp is outside range, then the output will held high~14V like that.
For this 14V, I should use high to low level shifter to feed in microcontroller right?