TRF7970A: ISO14443A-3 & -4

Hello Wilmer,

That code wasn't tested for NFC standards, it is meant as a simple RFID reader and the NDEF functionality is rudimentary at best. SLOA227 was tested directly against NFC standards however, but it's significantly more complex: http://www.ti.com/lit/pdf/SLOA227

One thing SLOC297 does not do well is tracking the g_bBlockNumberBit across commands, that would be one piece you need to handle. If you send the wrong one, then it would cause an issue. That is probably the most common issue you'd hit. The code also just is not setup to handle anything but a perfect data exchange and if anything goes wrong, it will stop there. There is no recovery/retry/error handling implemented in SLOC297. It also does not handle Wait Time Extension requests.

I'll reiterate that we spent a significant amount of time developing SLOA227. You are looking at a long process (I know I easily spent well over 100 hours to ensure interoperability w/ Android devices and I wasn't the only one working on the code) to get everything to work smoothly across all Android devices. This is not a trivial process, and really you need to be also referring the NFC Forum's official documentation at this point as the ISO docs alone won't cover all the finer details sufficiently to know how to implement them.