# Help identifying this chip (EEPROM?)

I have a circuit board from a Stratasys UPrint SE filament cartridge, and I'm trying to talk to the EEPROM on it. This board is unlike other Stratasys boards that I've seen people hacking with, and after a day or two of failed attempts to communicate with it, I'm wondering if I'm even using the correct protocol to interface with the memory chip.

I suspect that it's some sort of 1-wire EEPROM, but beyond that there is very little that I know for sure.

The top of the chip appears to have the markings:

331101
1309B1
442AA


I've Googled all around and can't seem to decipher what these numbers mean. I've checked two different chips, and they both have the same exact alphanumeric sequence, so it's not a serial number.

The main thing I want to know is -- what particular sort of 1-wire communication protocol do I need to use to talk to this thing? I've been attempting to use the Raspberry Pi's DS2433 library, but that doesn't seem to recognize this chip.

Thanks for the help!

Edit: Finally was able to initiate communication with the chip via a Raspberry Pi's 1-wire interface. However, the chip is showing up under family "b3" -- which is very odd, considering that I can't find reference to any sort of "b3" family in any of the w1 family specifications.

w1_master_driver w1_bus_master1: Family b3 for b3.1014d0006d00d.8a is not registered


I wonder if this is perhaps a custom chip of some sort that Stratasys created in an attempt to discourage hackers from accessing the chip? I'm very puzzled by 0xb3 as the family ID for this device.

• When all else fails you can add wires and use a logic analyzer to capture the communication. But I guess you know that. – Wouter van Ooijen May 19 '15 at 21:02
• That "AA" makes me think it may be some sort of 24AAxx... – Ignacio Vazquez-Abrams May 19 '15 at 21:07
• @WoutervanOoijen: Sadly the chip is embedded pretty deeply into the printer when it's in actual use, so capturing communication of it in action would be a bit of a beast. I hadn't thought of that though -- nice suggestion, thanks! – HanClinto May 19 '15 at 21:21
• I would try to connect to the connection points between the cartridge and the printer. – Wouter van Ooijen May 20 '15 at 6:08