0

I have used the PN7150 NFC chip from NXP in autonomous polling mode with LPCD disabled.

I can detect NFC Tag and can see NFC coil signals are changing as the NFC tag is detected.

PN7150 VDDTx current consumption is 25mA when NFC Polling is occurring and 230mA when NFC Tag is detected.

But when the NFC tag is removed, current consumption is still 230mA and signals are observed on the NFC coil same when a tag was detected. The image is attached herewith. enter image description here Is there is any way that PN7150 will stop RF activity as soon as Tag is removed without initiating

My questions are:

  • Why there is still RF signals visible even we remove a tag from the surface?
  • Can PN7150 notify DH if the NFC tag is removed?
  • Can PN7150 switch to RFST_DISCOVERY state after the NFC tag is removed??

I want NFCC(PN7150) to deactivate RF if Tag is removed from the surface.

Is it possible ??

Thanks in advance

Taher Kawantwala
  • 51
  • 11

1 Answers1

0

I figured out the answer after going through the reference manual and NCI documents The answer is: Yes, the PN7150 can notify the DH that the tag is removed. This is at the NfcLibrary, under the NXPNci directory. NxpNci_CheckDevPres() function, this function should return an NXPNCI_SUCCESS in case a device has been detected. Regarding the possibility of switching to RFST_DISCOVERY after a tag is removed, this state is triggered for discovering new tags, not after removing one. The DH needs to send the discover command again in order for this to happen. About the possibility of deactivating the RF, this will have to be implemented by yourself using the RF_DEACTIVATE_CMD which as mentioned in the User Manual

Thanks

Taher Kawantwala
  • 51
  • 11