Wireless Communication LSIs Compatible with the Wireless M-Bus Standard for Smart Meters in Europe

In recent years, efforts to establish smart meters have begun in several countries. The 868MHz band Wireless M-Bus transmission method, which is likely to become popular in Germany and the surrounding countries and ultimately adopted as the mainstream communication method in Europe, has 3 modes. Signals must be discriminated differently for each mode based on the operating function. Conventionally, packet processing for discriminating modes and messages was commonly performed by software on the microcontroller side, placing an extremely high load on the microcontroller, resulting in higher power consumption.

The ML7406, which supports the frequency band from 750MHz to 960MHz, is compatible with the ARIB STD-T108*2 standard in Japan as well as the global standard IEEE802.15.4g, making it suitable for a wide range of fields throughout the world, including smart meters and energy management systems (EMS).

LAPIS Semiconductor, in collaboration with Steinbeis developed specifications for hardware-based packet processing and integrated a Wireless M-Bus packet handler into the LSI. The packet handler is designed to perform hardware-based processing of a variety of functions, such as simultaneous standby for interoperability between C and T Modes, automatic discrimination of Format A and B messages in C Mode, and address filtering that automatically distinguishes whether packets are intended for this or other devices. As a result, microcontroller operating rate is reduced by about 20% compared with conventional software-based systems, significantly cutting device power consumption.

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LAPIS Semiconductor can supply sample software and C source code that include all of the T, C, and S Mode functions compatible with EN113757-4:2011 in the Wireless M-Bus protocol stack. In addition, an industry-standard OMS-compatible protocol stack that can be used without modification in OMS-based meters, along with Wireless M-Bus protocol analysis software, can be licensed from Steinbeis.

The 868MHz ML7406 joins the ML7344E, which is compatible with the 169MHz (N Mode) and 433MHz (F Mode) bands, completing LAPIS Semiconductor’s lineup for the Wireless M-Bus standard and ensuring compatibility with smart meter applications throughout Europe.

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Key Features

Wireless M-Bus packet handler
-Supports T, C, and S Modes
-Equipped with an automatic discrimination function for Formats A and B in C Mode
-Integrates an automatic discrimination function for C and T Modes
-Automatically executes operation and insertion of CRC data corresponding to each mode
-Can connect to conventional T Mode supporting a data rate deviation of 12%

General-purpose packet handler
-Functions as an IEEE 802.15.4g*4 packet handler based on register settings

Automatic Wakeup/Sleep, and high-speed carrier checking functions
-By controlling the built-in timer using internal 32kHz RC oscillation or external clock input, the LSI can periodically, without any instructions from the microcontroller, wake up from Sleep Mode, run in Receive or Send Mode, and then return to Sleep Mode. Combining this operation with a high-speed carrier checking function allows the microcontroller to regularly detect the presence of radio waves in the shortest time possible and, if no radio waves exist, go back to sleep.

Multiple sleep modes
-The ML7406 features five sleep modes (including Deep Sleep mode). The most suitable sleep mode can be selected based on system configuration and needs.