topic Re: NFC RF active error flag in Wireless MCU

NFC RF active error flag

Leeenka — Tue, 12 Oct 2021 06:49:25 GMT

Dear developers,

we have the PN5180 connected to Raspberry Pi. I have followed instructions from here https://www.nxp.com/docs/en/application-note/AN12650.pdf for the ISO/IEC 14443 - REQA. After I sent REQA command I repeatedly read IRQ_STATUS register to check the status and RX_STATUS to check number of bytes received. The number of received bytes are 0 and in the IRQ status reported bits are 1:2:4:5:10 and after I place a card also bit 0. What does mean that RF active error IRQ status? We also have not the BUSY pin connected. Could it also cause wrong behavior?

Re: NFC RF active error flag

Leeenka — Tue, 12 Oct 2021 10:55:32 GMT

Ok the status could be read from RX_STATUS register. I realized that after RF_ON command I am stuck on STATE_CHANGE_IRQ_STAT (I am waiting for TX_RFON_IRQ_STAT). In this moment I can see sinus vawes on oscilloscope. If I ignore it I will be stuck waiting for the RX_STATUS register to reflect the TRANSCEIVE_STATE. If I ignore both, the TX_RFON_IRQ_STAT appears after few SEND_DATA sequences. Is there any state diagram that could help me to diagnose the problem? For example which state may IRQ_STATUS register reflect after RF_ON command and so on? Any help is appreciated.

Re: NFC RF active error flag

Fabian_R — Fri, 22 Oct 2021 18:36:40 GMT

Hello LEEENKA,

Thank you for your interest in using our PN5180 bard for your design. Have you explored the possibility of using the board with our NFC Reader Library? There is a well-explained Application Note for guiding you on how to install NXP’s NFC Reader Library on a GNU/Linux system (AN11802).