RC522 tag detection interrupt

Forum / MIFARE and NFC Reader IC`s / RC522 tag detection interrupt

  • 6. January 2016 at 14:23
    Hi everyone,

    I have been struggling for the better part of the day on getting the interrupt working properly on the RC522 for card detection...

    If I understand the datasheet properly the MFIN (MIFARE Signal Input) should be set high when a card is detected, therefore the code I have written is as shown below (based on MFRC522 Mbed library). I have tried to change the registers and I can get interrupts to be triggered (the AlertLo for instance is high if I enable all the interrupts in ComIEnReg).


    RfChip.PCD_WriteRegister(MFRC522::ComIEnReg, 0b10110000);
    RfChip.PCD_WriteRegister(MFRC522::DivIEnReg, 0b10010000);

    RfChip.PCD_WriteRegister(MFRC522::ComIrqReg, 0x7F); // Clear interrupts
    RfChip.PCD_WriteRegister(MFRC522::DivIrqReg, 0x7F);

    Would anyone have any suggestions on how to trigger an interrupt when a card is detected next to the reader? I might have been missing something but the datasheet contains little useful information regarding the handling of interrupts. Any code sample showing this working would be appreciated (whatever microcontroller it has been coded for)

    Best regards,
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    Re: RC522 tag detection interrupt

    27. January 2016 at 15:59
    Hi, did you find a solution?
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    Re: RC522 tag detection interrupt

    27. January 2016 at 16:01

    No I didn't, I haven't worked this in a while but I was still hoping for someone to reply to this. I've seen many people online trying to get the interrupts to work but I don't think i've seen one person succeeding ...

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    Re: RC522 tag detection interrupt

    27. January 2016 at 16:25
    By the way. I believe you have to write 0x00 into ComIrqReg and DivIrqReg inorder to clear interrupts.
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