Freescale introduces single-phase electricity meter reference design based on Kinetis microcontroller

Customizable MK30X meter designed to increase accuracy and reduce cost of metering solutions for the residential metering market

AUSTIN, Texas – Feb. 25, 2011 – Freescale Semiconductor today announced a smart meter reference design that will be demonstrated during embedded world, March 1-3, 2011 in Nuremberg, Germany. The reference design, which will be featured as part of Freescale’s Smart Energy Wall display, provides a high-performance solution for power measurement in single-phase, two-wire installations targeted at the residential metering market.

According to a study prepared by Dr. Ahmad Faruqui of The Brattle Group for the Edison Foundation’s Institute for Electric Efficiency (IEE), this technology could save energy consumers more than a billion dollars annually for a population base the size of the US or Europe. With the growing consumption of energy worldwide, particularly in the residential market, utility providers need increasingly accurate and cost-effective energy metering solutions. Freescale’s MK30X single-phase electricity meter reference design addresses these accuracy and cost needs by providing efficient analog-to-digital converters (ADCs) combined with an embedded programmable gain amplifier (PGA) to increase the accuracy of energy measurement, along with a cost-effective shunt sensing circuit implementation and bill of materials (BOM).

The 32-bit Kinetis MK30X256 MCU at the heart of the MK30X reference design is based on the ARM® Cortex™-M4 core. This powerful core’s effective support of 32-bit math enables fast Fourier transform (FFT) based metering algorithms, which calculate metering quantities from elementary voltage and current harmonics. This calculation approach results in the precise accuracy of the reactive energy, as compared to other known metering algorithms.

The MK30X reference design includes a 128-bit unique identification and FlexMemory that provides every meter with an individual identifier and tamper detection. Firmware based on an MQX™ real-time operating system enables customers to design electricity meters based on their unique requirements and is well-suited for use in advanced markets.

“Our Kinetis line is the most scalable portfolio of ARM Cortex-M4 MCUs in the industry,” said Bruno Baylac, director and general manager of Freescale’s Metering, Medical and Connectivity Solutions business. “Our MK30X single-phase electricity meter reference design further demonstrates the versatility of the Kinetis line, as well as our commitment to providing accurate, cost-effective and customizable solutions for the smart energy market.”

Customization is available using the built-in LCD, which provides the standard metering values. The designer can choose any of the measured values by clicking on the device’s built-in buttons. The designer is also able to choose from several types of communication interfaces for remote collection of data. One option is connection to a ZigBee® network via an I2C interface, meaning the meter can easily be enabled as part of a smart grid network. The meter is also able to connect outside of the home via SCI/SPI for last-mile communication.

About the MK30X

The Freescale MK30X single-phase electricity meter reference design features:

* Kinetis MK30X256 MCU built on the ARM® Cortex™-M4 core

* 5 to 120A current range (nominal current is 5A; peak current is 120A)

* 85 to 264V, 50/60 Hz voltage range

* Active and reactive energy accuracy IEC50470-3 Class B1), 1 percent

* Line frequency measurement (for precision zero-cross detection)

* Cost-effective shunt-resistor sensing circuit implementation

* Low-power modes including the use of built-in RTC (Li-battery back-up)

* 4x40 segment LCD, including charge pump (values shown on LCD: V, A, W, Var, VA, kWh, kVarh, cos φ, Hz, time, date)

* Tamper detection via tamper button

* LED pulse outputs (kWh, kVarh)

* IEC1107 infrared hardware interface

* Optically isolated RS232 interface

* 2.4 GHz RF1322x interface (I2C daughter card) for connecting the meter to a ZigBee network

* EMC proven design (EN61000-4-2, EN610004-4)

* Multiple advanced metering algorithms (FFT, filter-based method)

* MQX real-time operating system

* Cost-effective bill of materials (BOM)

1) Target accuracy class to be confirmed by pre-certification testing


Freescale’s Kinetis MK30X single-phase electricity meter reference design is expected to be available in mid-April. For more information, contact a Freescale sales representative or an authorized distributor. For more information, go to

About the Freescale Technology Forum

Created to drive innovation and collaboration, the Freescale Technology Forum (FTF) has become the developer event of the year for the embedded systems industry. The Forum has drawn more than 40,000 customers at FTF events worldwide since its inception in 2005. Our annual flagship event, FTF Americas, will take place June 20–23, 2011, in its new location in San Antonio, Texas.

About Freescale

Freescale Semiconductor is a global leader in the design and manufacture of embedded semiconductors for the automotive, consumer, industrial and networking markets. The privately held company is based in Austin, Texas, and has design, research and development, manufacturing and sales operations around the world.