Component ID

[THATguy]

I want a way for components to identify themselves with an 8-bit binary code (assuming that gives me 255 codes)when attached to a system.
It needs to be very small, so I doubt I can just solder an IC on, unless I can get them in about 1x4x4ish mm size?
So I may have to do this with transistors, I only want it to Identify it's self with the initial power signal. They won't be hot plugged (at this stage) - plugged into live circuit.
Perhaps use a nand memory gate that remembers it has IDed its self, though this would require a reset before component is removed from system to ensure it would ID when plugged in again or to different system. The components will have a generic plug so they won't be able to distinguish by where they are plugged in. And if I had a 2.5mm, 3.5mm, and 6.25mm headphone jacks I'd like them to be distinguishable as 6.25 would require more power.
I will also have 6-8 communication wires on each plug, to send data over.

[Brumby]

Your description is rather vague.  For starters, what do you mean by "component"?  A better idea of what you are trying to achieve might help us come up with solutions or alternatives.

I'm also curious about what seem to be space constraints.  You say you could only accommodate a chip around 4x4mm - yet you are considering transistor solutions?  That just doesn't make sense.

[Brumby]

I will also have 6-8 communication wires on each plug, to send data over.

If you have 8 communication wires, you could just hard wire a code, which will give you 256 combinations.

[bktemp]

You are looking for a silicon serial number:
https://www.maximintegrated.com/en/products/digital/memory-products/DS2401.html
https://www.maximintegrated.com/en/products/digital/memory-products/DS28CM00.html
https://www.maximintegrated.com/en/products/digital/memory-products/DS2411.html
http://www.microchip.com/ParamChartSearch/chart.aspx?branchID=7046&mid=&lang=en&utm_source=MicroSolutions&utm_medium=&utm_term=&utm_content=MPD&utm_campaign=Unique+ID+EEPROM+Ad

[Brumby]

You are looking for a silicon serial number:
https://www.maximintegrated.com/en/products/digital/memory-products/DS2401.html
https://www.maximintegrated.com/en/products/digital/memory-products/DS28CM00.html
https://www.maximintegrated.com/en/products/digital/memory-products/DS2411.html
http://www.microchip.com/ParamChartSearch/chart.aspx?branchID=7046&mid=&lang=en&utm_source=MicroSolutions&utm_medium=&utm_term=&utm_content=MPD&utm_campaign=Unique+ID+EEPROM+Ad

Nice.

[THATguy]

Brumby
I just figured I could get a few transistors to do the job, it would be smaller than an IC, but I guess that is wrong.
Can you give me a link to how I would hardwire a unique code ? I just can't imagine where I would begin to do this, I would still need 2 or more wires for data transfer.
The components could be anything really, I want to make a kind of plug and play system.

Bktemp Thanks for those links I'll have a thorough look at those.

Can't thank you guys on mobile, but will when I get back on PC.

[Brumby]

Can you give me a link to how I would hardwire a unique code ? I just can't imagine where I would begin to do this, I would still need 2 or more wires for data transfer.

The idea of hard wiring a unique code was based on you having 8 wires/pins/whatever available for setting parallel data - but that doesn't seem to be the case.

This is where some more information would be helpful.

However, the suggestions from bktemp are more practical and capable.

[bktemp]

Given your size restriction you can't have a complex circuit for creating the ID code. Even a few transistors are bigger than the dimensions you have specified.
The silicon serial numbers are probably the smallest solution (the microchip ones are available in SOT23). And they use either I2C or a single wire bus, so you need only 3 wires, or less if you already have GND and a suitable supply voltage available).
Another idea would be using two voltage dividers with 16 steps each giving a total of 256 steps: 4 resistors are small and cheap and can easily be read by any microcontroller with an ADC.

[amyk]

I will also have 6-8 communication wires on each plug, to send data over.

If you have 8 communication wires, you could just hard wire a code, which will give you 256 combinations.

That's my thought too. Not even an IC or any semiconductor would be required - just a couple of solder bridges, and maybe a resistor, would be sufficient.