How can you secure a sensing node?

At Sensors Expo 2018 in San Jose, CA, Martin Squibbs, Product Marketing Manager for Microchip Technology discusses the company’s newest SAM L11 microcontroller (MCU), the first on the market to have the Arm Cortex-M23 core with TrustZone. Leveraging TrustZone, the three differentiating features of the 32-bit MCU are high security, parallel capture (through a two-stage pipeline) and extremely low power consumption.

ARM TrustZone capabilities include secure boot, secure boot loader, active shield and the ability to protect keys from cyber keylogging attacks.

The Water Tolerant Touch Demo in the exhibit demonstrates parallel capture of the chip which makes it much faster. The touch control has a shield that provides water tolerance as well as noise immunity.

The third aspect of the new MCU is low power. The ultra-low power 32-bit MCU family consumes less than 25 µA/MHz in the active mode, under 600 nA in sleep mode with full RAM retention and has a fast wake-up time of 1.5 µS. Tested to the EEMBC testbench, this is 50% less power than the nearest competitor.

A development kit is available for SAML11 and SAM L10, a version without the integrated hardware security, to test various features and especially the TrustZone. Working with partner Testonics, Microchip will offer tools to support the development of the security environment.

An example of how the security feature work in the Temp Sensor App, portions can be sandboxed within the device and they cannot be tamper with. Limited application programming interfaces (APIs) have access to the secure application (the temperature control). Non-secure applications can be built on top of the protected control in the same chip. If a non-secure application tries to do anything with the secure application, its access to the trusted environment is prevented.