Hello,
I have been working with the NTAG I2C Plus chip, my phone for NFC communication, and a MIMXRT1060 EVKB board for I2C, and it has been working well. Now I am trying to explore the authentication/password functionality, and it is going less well.
The datasheet has the following table for sending the PWD_AUTH, which makes sense other than the CRC. I did around 5 hours of research yesterday and I understand the idea of a CRC and how it is used, but no matter where I checked, including "Ref. 2" I could not find answers to a few questions.
1. Does the NTAG I2C plus use a specific polynomial and initial value, and what are they?
2. In general, do both devices that are communicating need to have a predetermined, agreed upon polynomial and initial value? (I saw a post where someone was saying as an option you could send these values along with your message, but I don't know if that is how the NTAG I2C Plus does it. I assume not since the CRC section of the above table says 2 bytes)
3. As an example, what would the CRC be for the default password 0xFFFFFFFF?
I appreciate any information you can provide, especially since to me this information seems so sparse on the internet.
