PN5180 RF field detection flag

[julieronday]

We are currently testing (immunity against radio fields) a badge reader using PN5180 chip with NXP NFC reader library v4.04 and firmware v3.5. The chip turns off its RF field in case it detects another field with a frequency between 11 and 15 MHz. We have read that this is an expected behaviour according to the NFC standards and we know how to disable this feature. However, while enabled, we would like to retrieve the information that the field has been turned off. We expect to have the RF_DET_STATUS in the RF_STATUS register set but it is not. We feel that configuration of the RF_LEVEL_DETECTOR_CONTROL could change this but the datasheet doesn't give much information about this register. Could you clarify the settings of this register? How to determine the lower and higher reference values for the RF level detector and which one is the lower? (Datasheet says that RFLD_REF_HI = lower!?)

[Kan_Li]

Hi Julie,

I think you may use IRQ_STATUS[RF_ACTIVE_ERROR_IRQ_STAT] to check this kind of events.

Have a great day,
Kan

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[julieronday]

Hello Kan,

Thank you very much for your answer. Indeed, IRQ_STATUS[RF_ACTIVE_ERROR_IRQ_STAT] gives the expected information. It seems strange that RF_STATUS[RF_DET_STATUS] doesn't give the same but it doesn't matter since I can use the other flag.

Best regards,

Julie