s3c is tantalizing us with this mystery EEPROM device. It’s a small I2C EEPROM data storage chip, and it appears to be powered parasitically from the I2C clock line.

Was bored today so I opened a dongle I had laying around. It only contains an I2C eeprom and a couple of passives but it’s pretty smart, it uses a diode and capacitor to power the eeprom from the eeprom clock line.

Anyone have an idea what the resistors R1 and R4 are for? I’m assuming PIN1 and PIN2 are connected to Vcc through external resistors and are connected as SDA and SCL for normal I2C operation.

We’ll send a free PCB to the poster with the most persuasive explanation of the circuit.

Advertisements