Energy Harvesting/VCC issue on the NFC04A1...

[damien_lobb]

Hello,

I have an issue with the energy harvesting functionality on the NFC04A1, which I believe probably has a very simple solution. If the reader is kept on the tag then EH is happening and working fine, then if i take the reader away from the tag, there is no power, as expected.

However, if I then put the reader to the tag again, although I get 3.3V at the jumper, none of my code will work. E.G. NFC04A1_NFCTAG_GetVCC_Dyn() returns an error indefinitely.

I can reset the program and its fine again, until it loses VCC again. This is a pain, as i find that if I put the jumper on constant VCC, the tag field can drop out randomly for a millisecond or so. If this happens with EH, it completely ruins the program.

I imagine I cant be the only one who has noticed this, so I'm sure there is a simple fix. I imagine that fix already happens in my init function, but it would be handy to pinpoint exactly the point that it does, rather than run a lot of needless code.

Thanks

Damien

[Ronald B.]

​Hello Damien,

You are correct, after a failed I2C communication, depending on the state of the I2C line, it may be required to reset the I2C of the MCU.

Unfortunately, in the NFC4 Cube package, the initialization function of HAL I2C driver does not toggle the SWRST bit.

So you would have to implement it in the application code.

Regards,

Ronald