Joint solution enables secure NFC transactions

This NFC solution is particularly well suited to very small, battery-powered products such as wearable devices and smartphones:

• the ams boostedNFC technology overcomes the difficulties that conventional NFC devices face when attempting to operate via a tiny antenna in an environment hostile to RF transmissions. The ams/ST solution exceeds the EMVCo requirements for RF performance in contactless payments, even when operating through an antenna smaller than 100mm²
• the ST SiP provides comprehensive support for all important NFC security standards worldwide, ensuring that the ARM mbed Wearable Reference Design can support secure transaction types required in IoT applications, including but not limited to contactless payments, automatic fare collection and access control
• the joint ams/ST solution achieves very low average power consumption, helping to extend battery run-time between charges, thanks to fully configurable power cycling of both the boostedNFC front end and the NFCC

The mbed Wearable Reference Design provides a model that wearable device OEMs can quickly replicate to achieve high-performance NFC card emulation. The joint ams/ST solution is particularly easy for system designers to work with, since it is supplied with a complete NFC software stack developed by ST. This stack is compatible with ARM’s mbed IoT Device Platform.

In addition, the high RF performance of the ams/ST solution ensures robust NFC functioning even in the most demanding operating environments. The NFC system draws on unique capabilities in the ams AS39230, which implements active load modulation. This boosts the NFC front end’s transmission signal to achieve an ‘operating volume’ – the space in which the wearable reference design can couple with an NFC reader – comparable to or exceeding that of a contactless card, which will typically have an antenna that is some 40 times bigger. The solution provided by ST and ams is also optimised for the mbed wearable reference design’s antenna, giving high immunity to interference from the wearable reference design’s Bluetooth and GPS radios.

At the same time, the close compatibility between the discrete ST and ams components provides for sophisticated power-saving capabilities: the ST54E may be held in a deep power-down mode when not in the presence of an NFC RF field. At the same time, the AS39230 cycles rapidly through its far less power-hungry active power modes, drawing an average current of just 18µA.

The ams/ST solution’s software is optimised for low-power MCUs based on ARM technology. Its modular design means that users can choose to compile only the modules for the use cases their device supports, helping to reduce the system’s memory requirement and to optimise the resource footprint.

The software stack optionally also supports peer-to-peer and reader/writer functionality and can be updated over-the-air when the device is in the field.

The ST54E is supplied to developers fully approved for use as an NFC device in card emulation, peer-to-peer and tag reader modes in compliance with the NFC Forum standards. It is also suitable for use in applications, which require worldwide certification, including for Common Criteria, EMVCo, GlobalPlatform and Visa, Mastercard, Amex, Discover, and the People’s Bank of China (PBoC).

In addition, the security capabilities of the mbed wearable reference design are enhanced by a separate fingerprint reader, which uses an STM32F411 Dynamic Efficient MCU from ST, based on the ARM Cortex-M4 core, to perform fingerprint image processing and matching.

“Our joint NFC reference design has been proven to provide the best combination of RF performance, interoperability and low-power operation available in the market today. Thanks to minimum system requirements in terms of footprint and processing power, the ams/ST solution is suited for space constrained designs, such as ARM’s mbed Wearable Reference Design,” said Mark Dickson, Director of Marketing, ams.

“The ams/ST comprehensive NFC solution provides an easy path to developing secure and energy-efficient wearable/IoT applications for contactless payment, ticketing, and access control,” said Laurent Degauque, Marketing Director, Secure MCU Division, STMicroelectronics. “Compatibility with the mbed IoT Device Platform will enable OEMs to go from prototype to product quickly and focus on adding their own value-add features.”

“The ARM mbed Wearable Reference Design provides a tested design foundation for companies to quickly build low-power IoT devices and focus on adding value with their own innovative features,” said Zach Shelby, Vice President of Marketing, IoT Business, ARM. “The NFC solution from ams and STMicroelectronics demonstrates the energy efficiency obtained by utilising ARM Cortex-M processors and the mbed OS for small form factor devices and applications.”