I'm planning to build a small wireless sensor, which should be equipped with an active NFC chip for simple pairing.
What it needs to do:
- Wake up the MCU when the tag is read
- exchange some data with our smartphone app to check for authentification
- probably change some settings of the NFC tag during manufacturing of the sensor
Now I had a look at the nt3h1101, which looks just like what I need, but I have a few questions:
- There is an external power supply (Vcc) for the i2c interface. Is this enough to read and write configuration data to the chip, or does it need an NFC energy field for that?
- What is the power consumption of the Vcc line, if the chip is idle (no NFC field, no I2C communication)?
- I see that there is a flag when new data was written over one interface and is ready to be read by the other. How does the application know the address of this data? Is there a standard for that, or do I have to come up with my own implementation in the application layer?