The smart water management system connects monitoring terminals, operational equipment, water meters, and other devices of water facilities (such as water plants, pump stations, and pipelines) to an Internet of Things (IoT) platform, enabling real-time automated monitoring, early warning, analysis, and management of water resources.

With the IoT transformation of data acquisition, Remote Terminal Units (RTUs) can connect to devices such as PLCs, sensors, and other hydrological data acquisition equipment. These RTUs feature low power consumption and communication capabilities like Bluetooth Low Energy (BLE)  and NB-IoT, which help establish a data monitoring system for hydrological and water management.

To meet the demand for ultra-low power smart water RTUs, Nuvoton has introduced the M2L31 series.

Features:

1. Battery-powered to achieve ultra-low power consumption.
2. Low-power data collection and transmission in standby mode.
3. Equipped with large-capacity memory, supporting Real-Time Operating System (RTOS).
4. Upon battery depletion, data is rapidly written and stored using ReRAM.

Ultra-Low Power Smart Water RTU Block Diagram

Nuvoton M2L31 Series Features:

1. Ultra-Low Power Consumption

• Normal operating mode power consumption: 60 μA/MHz.
• In RAM retention mode with normal power off: 2 μA.
• In deep power-down mode: 300 nA.

Additionally, the M2L31 features a unique automatic operation mode in its low-power domain. By configuring a low-power clock source, the system can transfer the collected data to low-power SRAM through a low-power serial interface without CPU intervention, creating the most power-efficient automated mechanism.

2. Unique Large-Capacity Memory

1. The M2L31 uses ReRAM (Resistive RAM) technology, which operates on resistance-based switching. Unlike flash memory (eFlash), which uses CMOS switches, ReRAM does not require page erasure, resulting in faster write speeds. ReRAM Dual Bank also supports OTA (Over-The-Air) updates.
2. Up to 168KB RAM, supporting RTOS.

3. Rich Peripherals

• Supports USB 2.0 Type-C PD 3.1 controller.
• Supports USB 2.0 FS OTG functionality.
• Supports up to 2 CAN FD interfaces.
• Supports EBI (External Bus Interface).
• Provides 16 capacitive touch interfaces.

M2L31 Internal Resource Block Diagram (Green modules represent low-power peripherals or resources)

M2L31 Product Selection Table