nRF52 NFC communications

RE: nRF52 NFC communications

nick — Mon, 29 Aug 2016 08:00:24 GMT

yes,NFC technology will be applied in retail, payment, asset management and many other industries in the furture,last month,I brought some NFC stickers on www.asiarfid.com/NFC-Sticker for my phone, it's really convenient.

RE: nRF52 NFC communications

AndreaO — Fri, 01 Jul 2016 12:00:16 GMT

I'll try the R_value you suggested. Yes, I measured 3V peak-to-peak between NRF1 and NRF2.

RE: nRF52 NFC communications

FormerMember — Fri, 01 Jul 2016 10:00:55 GMT

Okay, I see. Could you try to set the value of R_in to a fixed value, 32 or higher for instance and check if it works better? The higher the value of R_in is, the lower its value in Ohm is. What you also can check is the error status register and check if the field has been too strong.

By peak-to-peak, do you mean 2*amplitude? If so, the amplitude is 1.5 V, and that should work without any problems.

RE: nRF52 NFC communications

AndreaO — Thu, 30 Jun 2016 14:02:50 GMT

Thanks Kristin for your reply, actually I didn't fixed the R_in during tuning.

The 3Vpkpk is the maximum swing when the smartphone is in contact with the product, obviously is less if distance is some millimeters. And it doesn't work well in this situation.

This swing is the max I can achieve tuning the capacitor. I can change the capacitors to lower the swing, but i guess this leads to de-tuning, or not?

DVdd is set to 1.8V.

RE: nRF52 NFC communications

FormerMember — Thu, 30 Jun 2016 13:05:17 GMT

The reason that the communication doesn't work very well when the voltage over the NFC pins is more than 3v pkpk is that the maximum voltage swing should not exceed VDD, see nRF52832 Product Specification.

When you did the tuning, did you use nfc_settings.bat (set the internal R_in to a fixed value)? If so, remember that R_in should not be set to a fixed value when using NFC communication.

RE: nRF52 NFC communications

AndreaO — Thu, 30 Jun 2016 12:35:12 GMT

Update: our BGA nRF52 is revision 1, I tried the define HAL_NFC_ENGINEERING_BC_FTPAN_WORKAROUND but with no luck. Anyone can help?