Hello,
Is it somehow possible to output a 13.56 MHz signal from the nRF52 ?
Yes, I KNOW: Similar questions have been asked many times. The nRF52 cannot drive an 13.56Mhz field, because it only acts as a tag. So, please do not throw tomatoes at me for asking this questions once more :-)
So, why do I want to output 13.56 MHz?
We do not want to use the nRF52 for RFID communication. Instead, we use an external RFID transceiver IC.
In practice we have to periodically check if there is a tag out there. And we try to reduce average current consumption!!! One way to poll for an RFID card is to drive an unmodulated 13.56MHz carrier and measure with an ADC if the carrier amplitude is modified by an approaching tag. But enabling the external RFID transceiver IC and waiting for its crystal to start-up consumes power. So, why not generate this 13.56MHz carrier from the MCU (only for polling, NOT for communication)?
Since the nRF52 can demodulate 13.56MHz RFID there must be an internal 13.56MHz signal inside the chip. Can this be output to GPIO or the NFC pins? I do not need power. I can add external power transistors to amplify the signal.
Thanks for hints.
