ATSHA204A not responding on I2C

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Hi there,

 

I'm doing my first steps with the ATSHA204A crypto EEPROM. I created a little test application with a PIC16F as the host for I2C communication and the ATSHA204A EEPROM. First I only wanted to establish the communication over I2C bus and read out count, status/error and the 2-byte CRC. For this I am using the factory default of the I2C address which should be 0xC8 (like described in the Factory Default Test Data document). But the device does not acknowlegde this address at all (see attached screenshot). I don't know what I am doing wrong. Am I using the right address? Or is there anything else I have to consider when addressing the EEPROM?

 

Thanks for any advice!

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Total votes: 1

I was able to solve the problem:

After holding the SDA line to zero for a wake of the device, the SDA has to be held one for at least 2.5ms before sending any command to the ATSHA204A. In my code the wait of 2.5ms was missing and the device was therefore not responding after the wake call.