2021-01-16 08:15 AM
Hi all,
I put the EH_MODE to 0 to activate Energy Harvesting. The EEPROM is filled with zeros, so that the smartphone cant read a NDEF message but trying it for some time.
I am measuring the voltage on EH, in parallel i added a LED to visualize the EH function. The LED fluctuates, voltage is not stable. Its a fast blinking LED. Is it because the Phone tries to read the NDEF and therefore its going up and down? How do i active continues EH then? Is there a certain App needed? how can i force continued EH for some seconds? If i am reading a message from the tag, thats very fast (this is the reason i put zeros in the storage, to extend the time reading/trying and therefore seeing the LED blinking for longer).
Could someone give me some hints? I guess some basic understanding is missing ...
many thanks
I am using ST25DV ANT7 board (14x14mm Antenna)
17.01.2021:
I added a short video for explanation.
I guess what i see is the "Reader to tag" modulation, please see picture attached. How can i force the smartphone NFC to provide the 13.56 MHz without modulation? I could believe there is a certain EH function needed? Does the ST App has such Soltution?
2021-01-19 03:34 AM
Hello,
It would help to have a scope trace of the voltage output on VEH pin.
Can you put a scope on VEH an post it ?
Best regards.