Electronic – Unknown SOT-23-5 I2C device

eepromi2cidentification

I have a small board that stores some static and dynamic data: cc 80bytes of serial number, manufacturing date and a counter.
The board has two SOT-23-5 components: one is with CBOCX and one is with EC0d0 (?) mark on it.

enter image description here

On the board, the wires as as follows (from left to right): SDA, SCL, GND, PWR.
I have hooked a logic sniffer to the wires and checked the communication. The board communicates with I2C protocol. It seems these two components are slaves, with addresses 83 and 96.
I was assuming these components are EEPROM-s, and looked up many datasheets. I compared the command descriptions from the datasheets with the sniffed data, but the sniffed data is different.
For example the communication starts with this I2C commands when I plug in the board to the master unit:

  1. START
  2. 10100110 (write request for the 83 device) – ACK
  3. 01000001 – ACK
  4. 11100111 – ACK
  5. 00000000 – ACK
  6. 00000000 – ACK
  7. STOP

The response from the board for these sequence is 32 bytes of data.
If I hook the board on my arduino and send out the sequence above, the board responds the same 32 bytes also for me.

I'd like to read and manipulate the data, but I have no idea right now, how could I do it. What other could be these components, that stores data in SOT-23-5 package other then an EEPROM?

Your ideas are welcomed!

Thanks!

Best Answer

it may be one of those crypto chips which are used to avoid hardware clones or grey market counterfeit.

This type of chip often comes in sot23 format and contains a key and some crypto mambo jambo that is specific for the maker... i wouldn't be surprised that a chip like that has no label on it...

Related Topic