Developer Tip: NFC Reader Chips vs. NFC Controller Chips

A guest blog post by David Shalaby, TapTrack

A topic that sometimes warrants consideration when doing an NFC project is: what the difference between an NFC reader chip and an NFC controller chip? This may arise when you need an NFC reader for a custom application, where the off-the-shelf reader is not feasible for some reason. This blog post details the very important distinction between an NFC reader chip and an NFC controller chip. The designer must pay close attention when selecting which one is the best option for the project.

The first NFC chips that were commercially marketed were simply 13.56 MHz reader front ends. They implemented only a small part of the ISO 14443 standard; part two only. In total there are four parts to this standard, and the key difference between an NFC reader and a controller is that a controller handles all parts of the ISO standard while a reader will require the designer to implement a lot of it in the host controller firmware.

Essentially, an NFC reader simply takes data, and transmits it using the modulation and signaling specified in ISO 14443-2. It also receives data sent to it using this standard. An NFC controller, however, goes a few steps further and handles the the messy parts of the anticollision and selection process, as well as the additional framing required when using different tag technologies and NFC operating modes, such as card emulation and peer to peer. The takeaway here is that using an NFC reader chip requires a much more advanced level of NFC knowledge.

Development Time

Using NFC controllers vastly reduces development time and is the main reason semiconductor companies developed them.  What makes an NFC controller so advantageous is the microcontroller it includes that handles additional NFC protocol implementation, further relieving the designer of ominous firmware development.

There are three additional complexities handled by the NFC controller:

  1. The ISO 14443-3 anticollision procedure
  2. The ISO 14443-4 transmission protocol
  3. Additional framing and CRCs required by specific initiator/target configurations

Depending on what tag technology or target configuration the reader is communicating with, an NFC controller will automatically handle the required protocol and framing implementation specified by the NFC Forum.  Such implementations vary in complexity, but the main point is that using an NFC controller will make managing this transparent, from the perspective of the designer’s firmware. See figure 1 below (Image taken from ).

Deciding between an NFC Reader Chip and a Controller Chip

For rapid solution deployment, a smart NFC reader such as the Tappy (USB or BLE connected) can be a great tool.  With an open SDK and lots of built in NFC middleware, it can really simplify your reader implementation. See figure 2 below for the additional features a smart reader can provide.

NFC Controller chip vs. NFC reader chip

Cost

This is where the NFC reader chip is advantageous.  With the integrated microcontroller that relieves the designer of a lot of firmware implementation, NFC controllers are about twice the price of NFC reader front ends.  To put it in perspective, even the ACR-122U, a very cost effective and widely used NFC reader, uses an NFC controller as its chip, presumably for the reduced complexity required in the host controller firmware. NFC experts however sometimes recommend reader chips since they know the anticollision and transmission protocol well enough to implement such firmware.

Conclusion

All in all, the extra cost and power consumption of the NFC controller is worth it if it is economically viable in the intended application. The main reason of course is speed to market.  By letting the NFC controller do the heavy lifting for you, the designer can reach market readiness much faster. Keep in mind that even if the cost of the NFC controller hurts in the pilot/proof-of-concept phase, once the true scope of NFC functionality is determined, the true complexity of the firmware needed for a simple reader chip can be more clearly defined. For example, if your application uses a UID only system, whereby the UID of the tag is the only piece of information needed, then using a controller to start simplifies the prototype. Also, if your product gains traction in the market, migrating to a less expensive reader chip solution is not too painful, since only the UID detection procedure needs to be implemented. This is something that can be budgeted and even outsourced when a product is being taken from beta stage to market.

About our guest blogger:

David has worked in the NFC business for two years and developed numerous hardware and software implementations of NFC projects. He has extensive knowledge of the space both from a technical and business model perspective. Founder of the NFC startup TapTrack, David is recognized as an expert in NFC applications and has lectured at NFC educational events all over the United States and Canada. David holds an MBA from the Rotman School of Business (University of Toronto) and a BASc. in Electrical TapTrack is a full service NFC solutions provider with extensive experience and know how in both hardware and software NFC projects. They have a robust NFC cloud platform as well as their own innovative cloud connected and platform integrated wireless NFC readers. Follow TapTrack on Twitter: @Tap_TrackEngineering from the University of Waterloo.

TapTrack is a full service NFC solutions provider with extensive experience and know how in both hardware and software NFC projects. They have a robust NFC cloud platform as well as their own innovative cloud connected and platform integrated wireless NFC readers. Follow TapTrack on Twitter: @Tap_Track

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