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Configurable IC socket

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I would like to be able to design a circuit that would incorporate a ZIF socket that would take different chips for analysis. In other words, there would be some way of selecting what chip you are going to insert and it would wire the circuit appropriately.

An example application that I guess already does this would be an EPROM programmer.

I don't mind if this has to be done using a PIC or some such - it would be quite nice to have a display so I guess that would be logical.

If this works, I could envisage using a similar circuit in the future for auto configuration of many pins, say 50-80.

Could anyone suggest an easy way of acheiving this?

Thanks in advance!


That's not exactly a small project there. You would need a series of bidirectional programmable switches, I know they make them but I'm not sure where to begin looking for them.


I was thinking too inside the box, with CMOS switches. Jumpers looks like a nice and easy way to do it.
Crutschow, thanks for the link. That's interesting and I'd love one, but I can't afford that much right now. I'd also like the satisfaction of having built a solution myself, heh!

Jumpers would work but it wouldn't be a solution for the larger project... 70 jumpers? The point was to make something that is easy to use - virtually foolproof. Having to rewire 70 jumpers leaves too much risk of human error. I don't need the cheapest solution but the best ;)

I'll have a look into those switches. I was thinking along the lines of switches myself, but couldn't really think how to do it.

Thanks for the suggestions!


Then you're back and finding switching IC's to do it for you. With a micro controller to control the switching arrangement. Universal programmers use switches like this but I have no idea what IC's to suggest.


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I assume you don't have to switch +21V, +/- 12V or +/- 5V like we did back in The Good Old Days...:D

1) You start with the logic pins. Hook up each of the pins to a bidirectional I/O port pin, programmable as input or output. In the Old Days we used 8255A, but now there are better devices. You might not want to waste I/O on pins that are always power/ground but that's at the risk of a new device requiring a rewire. If you really like programming, the easiest way to get all the programmable I/O you need, might be a bunch of AVRs or PICs talking to one another.

2) You take each of the pins that are used for P/G by any of your chip family and put a switch from the pin to ground and/or power. This could be a low power MOSFET such as the 8-pin dual types. One example I recently got cheap on eBay is the FDS4953 (dual P). Bypass cap outside the switch to keep from bogging down the logic (yes this is a compromise). Protect from shorts with a few ohms in series, outside of the bypass caps.

You could use BJTs instead of MOSFETs as power switches to save money if you don't mind using a lot more components and having greater losses.

I would not need analog switches for the logic.
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Thanks for the replies!

Actually, whilst the initial project doesn't need it, my bigger project I'll hopefully use this in will require switching +5V, +12V and sometimes -5V also! The +5V could be around 10A so that will be interesting!

I've taken on board what you said and will have a play. Thanks!
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