NFC interference to the controller board

Thread Starter


Joined Dec 19, 2015
Hi all,
I have a "lock door system" project using the NFC reader PN532 with the microcontroller ATMEGA328P-PU.
I already finished the circuit and software of the project, when I test it I face some problems, the NFC reader make an interference to the controller board, the readerfreeze the controller and stop its process.
after some test I see that I should move the reader away form the controller board, so I redesign a new board to do this, now I force new problem, now the board isrestart when I use the NFC card !!!
also after some more test, I found that when I use an extension cable (of length more than 16 cm) between the board and the reader the system work so far so good. (I tried with lower length cable but it wasn't work)!

so how to solve this problem?!
how to eliminate this cable?! or what is the equivalent component of this extension cable?!

any help appreciated
thank you


Joined Dec 2, 2013
We need more info.
schematic, layout software all or some could cause this.
look at decoupling, current to supply when activated or just a reset.