I am assembling a few data acquisition fixtures and would like my software to be able to identify the fixtures programatically. I have a breadboard that I can use for basic circuits. The DUT signals come into the fixture, can interact with the circuits on the breadboard, then from there it is connected to the DAQ hardware.
The DAQ hardware has 16 available digital IO lines I can use. At first I thought I would just pull some of the pins up and down with jumpers to put an 8bit identifier but then I thought it would be cool if there were chips that presented a fixed value.
To clarify, I would like to direct connect a chips pins to my DAQ digital IO pins so that I can read a value encoded in the chip. This is to prevent someone tampering with it and generally raise the level of security for the solution.
I searched for such a chip but cannot find one. I do not want anything I need to program or that requires significant support circuitry; just looking for a super simple, single chip solution to put a fixed value on my digital lines.
BTW, in case it's not obvious: I'm an electronics newbie… big time.
Best Answer
Usually when we need something like that, an EEPROM is used. It's convenient to be able to change the numbers at will then lock them. Some EEPROMs are available pre-programmed with unique numbers such as MAC addresses.
For a few bits, these things are still available (called DIP shunts).
To program them to any of the 255 other possible combinations, you poke through the hole and break the connection as so:
Of course you could always use a DIP switch, but that would be easier to change.