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i2c issues during write when RF field of reader is in range

Question asked by vincent.joseph on Mar 10, 2014
Latest reply on Mar 10, 2014 by ST NFC

Hi,

I am sending this message because I am facing an issue using the M24LR16E-R.

 My i2c communication between my microcontroller and the M24LR16 chip works perfectly (I am able to read and write the entire memory multiple times with no problem) when no RF field are present.

 But when a reader becomes in range of the M24LR16 during a write, the M24LR is continuously answering NAK to all the message (even if I remove the reader !)


The functioning of the write procedure is a polling on the device with only Start (no STOP until I get a ACK) (As specified in this documentation §3.1 (http://www.st.com/web/en/resource/technical/document/application_note/CD00247968.pdf))

 Note :

-          No RF command is apply, the only fact of approaching the reader creates the issue

-          Reducing the i2c speed doesn’t change anything

-          I have verified my i2c signal using an oscilloscope and there is nothing to notice here.

 Do you know anything about this issue ?

 

Thank you by advance for your help.

 Don’t hesitate to ask me if you need more details on my setup / test.

 Regards

 Joe

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