Turnkey smart metering design

Smart metering is gaining momentum as the world’s leading economies overhaul outdated power grids and build out a smart grid that will improve how power is deployed and conserved. To help advance innovation in the energy management industry, Freescale has introduced a turnkey metering reference design built upon an advanced microcontroller (MCU) customized for the electrical metering market at the Metering Europe Conference and Exhibition, Oct. 6-8 in Barcelona.

The polyphase reference design, based on Freescale’s advanced MCF51EM256 ColdFire MCU, is a cost-optimized implementation of a single-phase or three-phase smart electrical meter. The reference design contains necessary hardware and software to make development of smart meters quick and easy, and was created to help developers reduce the cost and complexity of designing electricity meters for a wide range of residential and commercial applications.

With a rich set of integrated peripherals, including a 16-bit analog-to-digital converter with a programmable delay block, an independent real-time clock with calendaring function, dual secure flash memory banks, an automated meter reading (AMR) interface and a liquid crystal display (LCD) driver essential for smart metering applications, the MCF51EM family provides lower overall system cost, lower power consumption, reduces maintenance costs with remote firmware updates, makes it easier to secure and protect the meter and supports a wide range of display panels for smart meters.

“Freescale recognizes that embedded control and integrated connectivity will be at the heart of future smart grids and has developed a new generation of intelligent system-on-chip controllers specifically for smart grid applications,” said Aiden Mitchell, director of Industrial and Multi-Market Microcontrollers at Freescale. “Our goal is to provide developers with complete plug-and-play solutions designed to alleviate cost and time-to-market concerns, while bringing everyone a step closer to a unified smart grid.”

The new design was created and tested against the following International Electrotechnical Commission (IEC) standards:

• IEC 62053-22 International Energy Metering Specification, class 0.5 or
better for active energy

• IEC 62053-23 International Energy Metering Specification, class 2 for
reactive energy

• IEC 62056-21 International Energy Metering data exchange Specification

• IEC 62053-22, IEC 62053-23, IEC 62052-11 Electro Static Discharge
(ESD), tested per IEC 61000-4

The ColdFire V1 MCF51EM MCU family’s benefits include:

• 32-bit ColdFire V1 core - Additional processing power within the 32-bit
ColdFire V1 core, combined with a hardware multiply accumulate (MAC)
module, makes energy measurement calculations much more efficient
when compared to 8-bit solutions.

• Real-time clock (RTC) - Provides a real-time calendar to allow utilities to
implement different tariffs, as well as tamper detection mechanisms to
detect fraud.

• Firmware update - Two separate blocks of flash memory on the
MCF51EM allow a meter to continue operation on one flash bank while
the other is being updated with new firmware, avoiding costly downtime.

• Automated meter reading SPI - Provides a five-volt interface to external
AMR modems, eliminating the need for external components and reducing
system cost.

• LCD controller - The onboard LCD controller allows the MCF51EM to
control up to 288 segments with fewer pins than competitive offerings,
saving system cost to the end designer.

• The low-power blinking mode enables lower system power consumption
by allowing certain segments to be blinked on the display with the MCU
still in the lowest power mode.

Freescale also offers hardware and software development tools for smart meter applications based on the MCF51EM MCU family to help reduce development cost, ease design complexity and speed time to market. These tools include:

• Software code for calculating active, reactive and apparent energy.

• CodeWarrior Development Studio for Microcontrollers 6.2 with
complimentary Special Edition and Processor Expert rapid application
development tool.

• Complimentary Freescale MQX software including real-time operating
system (RTOS) source code, NTFS File System code, and a real-time
TCP/IP communication suite (RTCS).

• Online training, videos, webcasts, technical documentation and application
notes available at, and

The polyphase reference design is available now for loan and evaluation through local Freescale sales representatives. Reference design details are available at The MCF51EM256/128 devices are currently available for limited sampling, with broad availability expected in the first quarter of 2010. Suggested resale pricing will begin at $3.60 for quantities of 10,000 units.

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