I'm new to NFC and fairly new to programming as well.
I'm doing some research on NFC for a project that Im working on. I have an embedded device and a token that I need to get to communicate.
I need to have the token be the active device and the embedded device being passive. I cannot use an NFC tag in the embedded device, but need to an NFC chip. So both the token and the embedded device will have a chip, token chip working in active mode and embedded device chip working in passive mode.
My question is I can just have these chips be in reader/writer mode? During my reading I got the impression that reader/writer mode is only for reading tags - but could I use it between two non-tag NFC chips too?
During my reading I got the impression that reader/writer mode is only for reading tags - but could I use it between two non-tag NFC chips too?
Well, yes and no.
You can use a NFC controller in reader/writer mode to talk to another NFC controller in card emulation mode. In this case the second NFC controller just emulates a passive tag. As such, only the reader/writer NFC controller is able to initiate read and write requests, so you get unidirectional communication. You can extend this to bidirectional communication using polling though.
On the other hand you can put two NFC controllers in peer-to-peer mode. In this case you get bidirectional communication between the two NFC chips. However, this is mostly a high-level view. Under the hood one of the two NFC chips in a peer-to-peer session will again go into a state that is technically very close to the passive tag emulation mode.