I don't know where to ask but I was wondering if someone here has worked with it and could give some idea. Hope so.
A module ( MFRC522 ):
Schematic:
An MCU ( PIC18F452 ) is powered with 5V, module is powered from 5V(DC) -> 3.3V(DC) converter and all logic pins ( SS(SDA), SCK, MOSI, MISO...