The NuMicro M2351 microcontroller series is powered by Arm Cortex-M23 core and operates at up to 64 MHz frequency, with up to 512 Kbytes Flash memory and up to 96 Kbytes SRAM. The NuMicro M2351 series is embedded with TrustZone for Armv8-M architecture and Arm PSA with Nuvoton Secure Microcontroller Platform (NuSMP) Supported, which elevates the traditional firmware security to a new level of robust software security.

Arm TrustZone technology is a System on Chip (SoC) and CPU system-wide approach to security. In addition to the firmware-level security, the NuMicro M2351 series offers a more enhanced software-level security for more robust security and greater power efficiency. Furthermore, the TrustZone architecture could benefit the collaborative software development business model with rapid development and robust intellectual property protection.

In addition to TrustZone technology, the NuMicro® M2351 series is also equipped with rich functions to enhance system security. The Secure Bootloader supports trusted boot feature. The hardware crypto accelerators, including ECC, support encryption and decryption operations to offload processor-computing power. The KPROM is a password protection mechanism to allow Flash memory write and erase. The XOM defines execute-only memory regions to protect critical program codes. The Flash lock bits are designed to disable external Flash read/write and debug interface. Tamper detection pins can detect the state transition on the tamper pins.

In addition to security, power consumption is also critical for IoT applications. M2351 Series offers multiple power modes for more efficient power management. Regarding the power consumption of M2351 series, the normal run mode consumes 97 μA/MHz in LDO mode and 45 μA/MHz in DC-DC mode. The current consumption of stand-by power down mode is 2.8 μA and the deep power-down mode without VBAT is less than 2μA.

The Platform Security Architecture (PSA) is a holistic set of threat models, security analyses, hardware and firmware architecture specifications, and an open source firmware reference implementation. PSA is a contribution from Arm to the entire IoT ecosystem, offering common ground rules and a more economical approach to building more secure devices.

Nuvoton has developed the Nuvoton Secure Microcontroller Platform (NuSMP) to support Arm PSA. The NuSMP is a range of hardware and software mixture technology for security requirements of general purpose and secure IoT microcontrollers. With NuSMP, developers can easily achieve the secure services with the M2351 Series microcontroller in coverage of: Trusted Boot (Root of Trust), Secure OTA (Over-The-Air) firmware update (including secure software download), Power Management APIs for non-secure world and PC side crypto related development software tool.

Committed to providing an easy development experience, Nuvoton offers the free-to-use Keil MDK Nuvoton Edition for M2351 series. Besides, IAR Embedded Workbench for Arm and GCC are also supported. For supporting tools, M2351 Series offers helpful tools to aid the project progress. For example, the TrustZone Template Generator could assist the security state planning and the secure firmware building; the Crypto Tool could support the cryptographic requirements of M2351 series, including key generation, key exchange, digital signature, encryption and decryption. For security project developing, Nuvoton offers NuSMP (Nuvoton Secure Microcontroller Platform) of integrated security technologies. The application note, sample code and training videos for each technology would be available for developers to access and reference. Lastly, the Arm Mbed OS for IoT solutions and the Segger emWin for interactive interfaces are both supported in M2351 Series.