how Universal IC testers work?

[Lord Loh.]

Universal IC Testers.

I was wondering how Universal IC testers work. While most ICs have a fixed position for VCC & ground, some ICs have different VCC & ground positions.

If a Vcc & ground are applied to wrong pins, then the IC shall see them as signals without applying Vcc & ground. Will this not damage the IC? How is the set done then?

In case of microcontrollers, some give out their signatures at +12v. While others have absolute maximum ratings of 5.5v. How do these device work then? And what if 3.3 v devices are to be tested with the same device?

And to add to all the trouble, devices have different pin counts.

I actually want to build a universal programmer. And the first step would be to detect the device in the socket.

 

[tvthang]

Re: Universal IC Testers.

Hi, acording to me, VCC in universal IC tester is often connected with a resistor about 100 ohm, so if it connects wrong to pin of ICs that is not to damage device and additional time of test cycle is too short to damage devices.

 

[~E3016~]

Re: Universal IC Testers.

ussually the tester have limitations such as what kind of IC(s) which can be tested, either by pin counts or the functions of the pin

i think it should be enough to make the 'universal' programmer that can burn the 'universal' ic. i mean the ic(s) that have the same pins for examples. note that almost TTL IC have fixed positition on vcc and gnd - whatever the products

 

[Lord Loh.]

Re: Universal IC Testers.

Hi, acording to me, VCC in universal IC tester is often connected with a resistor about 100 ohm, so if it connects wrong to pin of ICs that is not to damage device and additional time of test cycle is too short to damage devices.

So with a resistor in series with Vcc shall be okay if Vcc ends up at the wrong pins?

If I apply Vcc to pin 40 of an AVR assuming it to be an 8051, The AVR shall see a Logic 1 at port A.0 without a Vcc. Could this damage the AVR?

 

[rikie_rizza]

Universal IC Testers.

Woah, what is this universal IC tester? Here I test so many IC and non of them are universal. there's an interface board which must be connected to a tester.