How NFC Forum CR13 Will Bring Wireless Keys to Every Car Door Handle

The NFC Forum published the Certification Release 13 (NFC Forum CR13), which enforces version 3.0 of its Device Requirements. One of the main additions, compared to NFC Forum CR12, is the support for the CCC (Car Connectivity Consortium) Digital Key Reader for car doors and Digital Key CE (Card Emulation) on smartphones. In a nutshell, CR13 will ensure that carmakers offer interoperable key systems using NFC. There are other features, but any attempt at an exhaustive dissertation would be futile. Let us thus explore what CR13 means for the automotive industry and its consumers.

NFC Forum CR13: What’s Wrong With Contactless Car Keys Today?

Consumers are at the mercy of proprietary systems. One car model could work with one generation of phones, but a newer automotive could have different requirements. As a result, the lack of industry coordination can leave customers frustrated and unwilling to adopt this new technology. NFC Forum CR13 also aims to make contactless car keys more practical. For instance, it mandates the use of a key even if the phone is in reduced power mode. When the smartphone is off and only showing an icon asking the user to charge it, makers must maintain a minimum charge for NFC operation. Hence, customers no longer need to worry about battery life when using a phone as a key.

NFC Forum CR13: Solving the Interoperability Issue to Reach Mass Adoption

The Reasons Behind NFC Forum CR13

Phones compliant with NFC Forum CR13 will be ready for CCC requirements. Additionally, most smartphones compatible with CR12 and EMVCo payment requirements should also pass CR13 certifications. Hence, the new Certification Release builds on existing standards with the aim of offering greater interoperability. Similarly, ST’s ST25R3920 offers one of the most advanced waveshaping capabilities, now essential for NFC Forum CR13 readers. Indeed, strict waveshape monotonicity tests are already in place in the EMVCo 3.0 standard when using NFC Card for payment, and the NFC Forum’s latest efforts aim to harmonize testing protocols among various standards.

Waveshaping is a method that adjusts the signal to better match PICC (Proximity Integrated Circuit Cards) references. Its objective is to avoid overshoots and communication errors. Put simply, it’s possible to fine-tune coupling operations between the reader and the card without requiring rematching. For automotive makers, waveshaping is essential to meet the more rigorous standards put forth by the new certification release. For consumers, the standard means that more phones and door locks will become interoperable, therefore improving the user experience.

Adoption of NFC Forum CR13

Traditionally, the industry takes about three years for a certification release to reach mass adoption. However, the NFC Forum is extending the grace period for makers to adopt CR13. Indeed, companies will now have 72 months, instead of 18, to move from the previous certification release to the new version. The NFC Forum thus takes into account the much longer development cycles in the automotive industry.

Yet, we can expect the transition to be quicker than usual. Indeed, most smartphones released today are compatible with NFC Forum CR13. Manufacturers will only need to release a software update to bring their operating system up to par. Similarly, the hardware and software to create compliant readers are already available. For instance, ST offers an RF abstraction layer for the ST25R3920, the STSW-ST25RFAL002, which facilitates the creation of readers compatible with CR13.

NFC Forum CR13: Thinking About NFC Door Locks, Center Consoles, and More

What’s Special About NFC Car Key Readers Is That They Don’t Have to Be Special

NFC modules in cars are in three primary locations: the door handle, the B-pillar between the front and backside windows, and the center console inside the vehicle. The first two control the access to the vehicle by unlocking the doors and allowing for very different designs. The space within the door handle is tiny, thus requiring slim components and antennas. On the other hand, the B-pillar enables coils four times larger. All three locations play a different role. For instance, the module in the center console can authenticate a smartphone to adjust seat positions automatically. We could also imagine a parent setting various speed limits when pairing the car with a teenager’s phone.

The trap for decision-makers and designers is to think that the three locations require entirely different systems. The strength of a reader IC like the ST25R3920 is that it can fit into all three areas. For instance, its vast operating temperature range of -40 ºC to +105 ºC means that it works indoor and outdoor. The ST25R3920 easily fits anywhere in the vehicle, from the door handle to the center console. And having only one IC means only qualifying one component, thus greatly simplifying designs and operations.

What’s Surprising About Designing NFC Modules with ST is The Unsurprising Path to Design

Anyone interested in the ST25R3920 can grab an inexpensive X-NUCLEO-NFC06A1 expansion board. The platform uses the ST25R3916, which is identical but didn’t go through automotive certifications. We even offer a MISRA-C compliant firmware, the STSW-STM8-NFC5, for testing on our NUCLEO-8S208RB baseboard. Moreover, we provide an antenna matching graphical user interface, the STSW-ST25R004, and a separate antenna matching tool in eDesign Suite, to further facilitate developments.

A strong hardware and software ecosystem is fundamental because it reduces the time to market. For example, by merely using the X-NUCLEO board, developers can take advantage of the automatic antenna tuning and the ultra-low-power wake-up sequence. Engineers can then decide to add the same components in their final design, porting the code they used on the development boards. Hence, we’re not merely offering a product but a path to an application.

A couple of years ago, engineers needed to convince decision-makers to use NFC in vehicles. Then Mercedes adopted our ST25R reader in their E-Class models. Now, managers want a reader because keyless entry and smartphone pairing are all the rage. Hence, a successful design is future-proof and can anticipate where the industry is heading. An ST25R3920 NFC reader and an STM8 MCU are can already create NFC Forum CR13 readers. Hence, investing in those components will yield returns for many years.

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