I am using the nfc library (nfc_t4t_lib) on the NRF52832 chip with SDK 17.0.2. When I approach the NFC antenna with a nfc reader (like a smartphone) and leave the reader on the antenna, the current consumption goes up to 2mA constantly. How can it be power optimized.
Hi,
I'm not sure if this can be power optimized. The phone may keep reading/polling to check if the device is still present after you receive the first NDEF_READ event, and the nRF does not know if/when the phone will request a full new read in the future. Therefore, the nRF needs to keep its RX enabled while the field is present, to be able to receive packets when the poller wants to send something. In the activated state, NFCT has a run current of 480 uA in addition to HFCLK and EasyDMA currents, which should correspond quite well with your measurements.
Here you can see an example of the events generated by the nRF when the field is present. As you can see, packets are both sent and received at regular intervals:
The only workaround I can think about is that you disable the T4T library after the first read if you do not want the poller to read again, then wait for the FIELDLOST event before re-enabling the T4T library. This will prevent devices from reading multiple times or write to the tag, and I'm not certain how stable it will be.
Best regards,
Jørgen
