Nuvoton NuMicro M55M1 low-power Arm Cortex-M55 MCU enables on-device AI with Ethos-U55 NPU

Nuvoton’s NuMicro M55M1 is a low-power AI MCU that combines a 220 MHz Arm Cortex-M55 CPU with a 111 GOPS Ethos-U55 NPU to run basic AI tasks on-device. It specifically targets small IoT and embedded devices that need low-power voice, audio, or simple image processing.

The chip embeds 1.5 MB RAM, 2 MB flash, and supports external OctoSPI/HyperRAM memory. Connectivity options include Ethernet, USB-OTG, CAN-FD, I3C/I2C/SPI, SDIO, and an 8-bit camera interface, along with ADCs, DACs, comparators, PWM, and multiple low-power modes.  It’s built for secure IoT applications with Arm TrustZone, secure boot, AES, and PSA Level 2 certification. Typical uses include voice triggers, smart sensors, simple vision nodes, small appliances, and industrial monitoring devices.

Nuvoton NuMicro M55M1 specifications:

• CPU Core – 220 MHz Arm Cortex-M55 core
  • Architecture – Armv8.1-M with
    • Helium M-Profile Vector Extension (MVE)
    • Arm TrustZone Technology
    • DSP extensions
    • Hardware Floating-point Unit (FPU), double-precision
  • Cache – 16KB I-Cache and 16KB D-Cache
• NPU –  Arm Ethos-U55 micro-NPU @ 220 MHz, 256 MACs, 110 GOPS, supports 8-bit and 16-bit integer operations
• Memory – 1552 KB (1.55MB) total on-chip RAM with,
  • 1344 KB SRAM (Bank 0: 512KB, Bank 1: 512KB, Bank 2: 320KB)
  • 8KB SRAM (Bank 3)
  • 8KB SRAM in low-power (LP) domain
  • 64KB I-TCM and 128KB D-TCM
  • Supports SPI/HyperBus interface (SPIM) for external memory
• Storage
  • 2x Secure Digital Host Controllers (SDHC/SDIO)
  • 2MB (2048 KB) on-chip dual-bank APROM, supporting OTA upgrades
  • 8KB on-chip Loader ROM (LDROM)
  • 3KB One-Time Programmable ROM
• Camera – 8-bit Camera Capture Interface (CCAP)
• Networking – 10/100Mbps Ethernet MAC with RMII interface
• USB
  • USB 2.0 High-Speed OTG with on-chip transceiver and Power Delivery (PD)
  • USB 2.0 Full-Speed OTG with on-chip transceiver
• Audio
  • 4-channel Digital Microphone Input (DMIC) with Voice Activity Detection (VAD)
  • 2x I2S (standalone)
• Other peripherals
  • 10x UART
  • 2x CAN FD controllers
  • 4x I2C, 1x I3C
  • 4x SPI / I2S
  • 2x QSPI
  • 3x Smart Card (ISO-7816-3)
  • Universal Serial Control Interface (USCI)
  • 8-channel Programmable Serial I/O (PSIO)
  • 1x LPUART , 1x LPSPI , 1x LPI2C (Low-Power Serial)
  • Up to 24-channel PWM (from 2x 12-ch EPWM and 2x 12-ch BPWM)
  • Analog
    • 1x 12-bit ADC, 5 Msps SAR EADC (up to 24-ch)
    • 1x 12-bit LPADC, 2 Msps Low Power SAR LPADC (up to 24-ch)
    • 2x 12-bit DAC, 1 Msps DAC
    • 4x Analog Comparators (ACMP)
• Timers – Total of 4x 32-bit timers, including
  • 2x 32-bit Low Power Timers (LPTMR)
  • 2x Tick Timers (TTMR)
• Misc
  • 4x Enhanced Quadrature Encoder Interface (EQEI) for motor control
  • 4x Enhanced Input Capture (ECAP)
  • 2x Watchdog Timers (WDT)
  • 2x Window Watchdog Timers (WWDT)
  • Real-Time Clock (RTC) with separate VBAT power domain
  • 8×6 Keypad Interface (KPI)
• Power – 1.71V to 3.6V
• Packaging
  • LQFP176 (24x24mm)
  • LQFP128 (14x14mm)
  • LQFP64 (10x10mm)
• Temperature Range – -40°C to +105°C

In terms of software support, the M55M1 series works with Keil MDK, IAR EWARM, and GCC through NuEclipse or VSCode. Nuvoton provides tools like NuTool PinConfigure, Pin-View, ClockConfig, and NuConsole for pin setup, clock configuration, and debugging. The MCU supports FreeRTOS, Zephyr, and RT-Thread, and can use GUI libraries such as emWin, LVGL, and Qt for MCUs.

The company also provides the NuMaker-X-M55M1D development board for Nuvoton’s Arm Cortex-M55–based NuMicro M55M1 microcontrollers. The board offers full-pin expansion, Arduino UNO-compatible headers, a mikroBUS socket, HyperRAM, Ethernet PHY, CAN FD, Wi-Fi module, audio codec, MEMS microphone, MPU6500 sensor, dual USB (FS/HS), and a microSD card slot.  Power options include 5V/3.3V inputs and an ammeter connector for real-time consumption measurement. The detachable Nu-Link2-Me debugger provides SWD, online/offline programming, and VCOM. It also supports add-on modules like a 5-inch capacitive-touch TFT display and a 720p CMOS camera, allowing developers to quickly test HMI, AI, sensing, and connectivity features.

Previously, we wrote about other Cortex-M55-based MCUs such as Ambiq’s Apollo330 Plus, Alif’s Ensemble family, and Renesas’ RA8M1 series, which are designed for similar on-device AI workloads for low-power, high-performance embedded applications. Like the NuMicro M55M1, these chips also feature DSP/ML capabilities through Helium extensions, optional AI accelerators, or wireless connectivity, and are designed for sensor hubs, IoT nodes, voice interfaces, and human-machine interaction workloads.

The M55M1 series includes the M55M1R2LJAE (64-pin), M55M1K2LJAE (128-pin), and M55M1H2LJAE (176-pin) are listed on Mouser but are currently non-stocked with a 30-week lead time. Prices come to roughly $8.50–$9.80 for the smaller packages and about $17 for the 176-pin model. The NuMaker-X-M55M1D development board is available for $212 from Nuvoton, which is rather pricy. More information, along with the documentation, can be found on the product page and the press release.

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