NFC not working with some phones like iPhone 11

Question

I am using nRF52832 SDK 15.3 and type 4 tag and some phones like iPhone 11 and Samsung S20+ are not able to detect the tag. The tag works with other phones so I don't think it is a hardware problem. I don't see the NFC_T4T_EVENT_FIELD_ON event. I just see some NFC_T4T_EVENT_FIELD_OFF events. I am doing initialization like this: 
 nfc_t4t_setup(nfc_callback, NULL); 
 
 Do I need to modify any parameters when initializing?

Einar Thorsrud · Accepted Answer

Hi,

I see the same on my side when testing the writable_ndef_msg example. The NFC_T4T_EVENT_FIELD_ON event is never received, perhaps because it seems the field goes on and off quite fast. I see this behavior using iPhone 11, but not using another Android phone for comparison.

For reference, this is a log where I use the writable_ndef_msg example from SDK 15.3 with the only modification that I also log NFC_T4T_EVENT_FIELD_ON and NFC_T4T_EVENT_FIELD_OFF when detected in nfc_callback() in main.c:

<debug> ndef_file_m: FDS event 0 with result 0.
<info> ndef_file_m: NDEF file record not found, default NDEF file created.
<debug> ndef_file_m: FDS event 1 with result 0.
<info> ndef_file_m: FDS write success.
<debug> nfc_platform: Utils init
<info> app: Writable NDEF message example started.
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
<debug> nfc_platform: Field detected
<debug> nfc_platform: Field lost
<info> app: NFC_T4T_EVENT_FIELD_OFF
...

I need to look into this a bit and get back to you.

Update: This is likely related to how the iPhone 11 detects the tag, where it uses very short NFC pulses. This seems to be less of a problem with the NFC driver in SDK 16 and 17, so I suggest you consider migrating if possible.

NFC not working with some phones like iPhone 11

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