SoC Is Hot for Smart Metering

You know a market is hot when multiple IC companies release platforms for the same market nearly simultaneously. Such is the case with Maxim Integrated (sponsor of the Integrated Nation site) and STMicroelectronics (STMicro). Both recently launched system on chips (SoCs) or SoC-based platforms for the smart metering market and other smart grid applications.

Both product lines include significant integration, including analog and mixed signal, to provide more functionality useful in metering and power monitoring applications.

Maxim recently released the Capistrano reference platform for smart meters and other smart grid applications. In its press release, Maxim cited some highlights of the platform, including 0.1 percent accuracy over an 8000:1 current range, an integrated application processor, a dedicated security co-processor, another microcontroller for metering, and a front end with digital signal processing (DSP) for metering. Here's a block diagram of the Maxim platform, including the Zeus SoC.

Figure 1

Maxim Capistrano Smart Metering Reference platform. In the blue box are the functions integrated into the SoC that is the heart of the platform.(Source: Maxim)

Maxim Capistrano Smart Metering Reference platform. In the blue box are the functions integrated into the SoC that is the heart of the platform.
(Source: Maxim)

I reached out to Timery Crawford, corporate communications manager at Maxim, to get a few more details. She told me there are up to seven ADCs, which are “typically targeted for energy consumption measurement, [although] they could be purposed for other measurements.” She also stressed the high level of integration, which includes the ARM M3, a 32-bit RISC processor in the metering section, and a 32-bit DSP core doing raw measurement processing. All of these are part of the Zeus chip. The figure below shows the reference platform, which provides the designs to integrate display, control (such as PLC), communication, and sensors into the complete system.

Figure 2

Maxim Integrated's Capistrano reference platform for smart metering.(Source: Maxim)

Maxim Integrated's Capistrano reference platform for smart metering.
(Source: Maxim)

I asked Crawford to compare this new platform to Maxim's line of metering SoCs, such as the 71M653x series. Basically, the Zeus product takes all the measurement functions integrated in the earlier series and adds the ARM processor, which can run communication stacks, over-the-air software upgrades, plus the security co-processor.

If you follow industrial networked sensors, you know that security has become a big concern. Maxim's new platform seems to be a direct response to industry trends and concerns. In fact, it indicated that the Zeus is the first to integrate so-called elliptic curve encryption methods.

The day after Maxim announced the Capistrano platform, STMicro unveiled the STCOMET10 product line, which it called the “Industry’s First Smart-Meter System-on-Chip.” Michael Markowitz, director of technical media relations for STMicro, referring to the large SOGRID in France, told me the new SoC will be “the core technology for processing and transmission of digital data for the entire grid, becoming the key enabler for smart grid in France.”

This block diagram shows what is included in the STMicro SoC, alongside a photo of the TQFP176 package.

Figure 3

STMicroelectronics STCOMET10 block diagram, left, and TQFP176 package, right.(Source: STMicroelectronics data brief and website)

STMicroelectronics STCOMET10 block diagram, left, and TQFP176 package, right.
(Source: STMicroelectronics data brief and website)

It appears that STMicro is positioning this IC as the first smart meter SoC based on the level of integration, which is extensive. The metering section includes three 24-bit Δ-Σ ADCs, which Markowitz said are suitable for class 0.2 meters (ANSI C12.20-2010 0.2 accuracy class, or 0.2 percent accuracy) or better. The data brief indicates that the analog front end (AFE) has 3.6 kHz bandwidth and delivers <0.1 percent error over a 5,000:1 range. The other AFE can be used for power line communications and includes both the line drivers and the ADCs.

Like the Maxim product, the STCOMET10 includes several processors, with an ARM M4 as the main processor which can run the communication protocol stacks as well. Both designs integrate energy calculations and DSP in hardware and embedded security. STMicro says the STCOMET10 supports AES 128/192/256 encryption. It is interesting to see the crypto featured so visibly in the press releases and literature from both companies. Maxim may be able to claim an edge here, having already adopted elliptic curve encryption methods. In his MOOC on cryptography, Professor Dan Boneh of Stanford University says there is a “slow migration to elliptic curve methods,” though AES256 is considered very strong at present.

Both the Maxim and STMicro designs have high levels of integration, though the STMicro SoC contains more than Maxim's. However, by providing a complete platform reference, Maxim makes it especially easy for designers to use its product. Are you working within the smart energy space? What do you think of these new, highly integrated products?

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21 comments on “SoC Is Hot for Smart Metering

  1. eafpres
    October 29, 2013

    Maxim has informed that the information source for the material is Kris Ardis, Executive Director of Energy Solutions at Maxim Integrated.

    I note that Kris published an article on EDN last year about the chip that is the heart of the platform.


  2. Brad_Albing
    October 29, 2013

    @Eafpres – thanks for the added info plus the link. This is a growing field with the power companies wanting to get more customers involved. And more IC companies are exploring entering the market with product.

  3. samicksha
    October 29, 2013

    Any expressions on system in package (SiP) comprising a number of chips in a single package, although i agree, SoC is taken as more cost-effective than SiP as its packaging is simpler.

  4. eafpres
    October 29, 2013

    @samicksha–My simple view is that the larger the market, and the more common the requirements, the more likely to see higher integration levels.  Seeing these SoCs indicates that the Smart Energy market indeed is thought to be very large as designing and launching an SoC with these levels of integration is a big commitment.  It is interesting to me they add a high-power application CPU capable of real-time OS, and they put both metering DSP and security co-processor inside too.  

  5. rvandewalker
    October 30, 2013

    Capistrano is really a software-development platform for new meters. There's some special things about it.

    The separated application processor, for example, means that even if the network-facing CPU fails from a subtle, well-funded attack, (say, by gangsters who develop a trust attack by misusing resources from the open-source community) the measurement & metering code cannot be subverted.  Most other “secure” metering ICs depend on the operating system and memory-mapping to separate the metering code from network-facing code.  And, most of this code is now open-sourced, and not extensively vetted for security.

    A meter's power supply is always tricky, because it can introduce noise into the measurements.  Capistrano applies Maxim's power supply technologies: After power-failure, the power line modem can require several Amps for 100ms to send a “mains sag” message.  Despite this, the supply is one of cleanest that Maxim's meter applications group has ever tested.  (Yes, Maxim groups razz on each other.  I'm happy to say I can brag about the power group.)

    Another item, not too visible, is that this is communicating meter data in IPv6 over OFDM power-line communication (G3), also by Maxim.  And, it's doing it in a small, affordable embedded software environment, not an expensive, cellphone-style Linux platform like the competitors.  The daughter PCB on the left is the G3-PLC modem.  Since an IPv4 address now costs $0.30, IPv6 is a strategic advantage in the BOM.  Cutting the memory cuts the cost.

    We also have partners for the socket on the right, which can support a Zigbee radio that talks to in-home energy monitors and thermostats.  Unlike most Zigbee vendors, our partners ported their Zigbee stack to run inside the main meter SOC's Arm application CPU, to get a more affordable total package.  Their Zigbee modem is a pure radio, less expensive than solutions with built-in Zigbee code and CPUs to run it.

  6. eafpres
    October 30, 2013

    @rvandewalker–Thanks for adding so much detail; this is a very interesting area and something where integration, mixed signal electronics, and embedded processing and software bring real advantages.

    We talk a lot here about what integration makes sense and what does not; this is an excellent case study with many lessons for design engineers as well as applications developers.

    Thanks again,

    Blaine Bateman


  7. etnapowers
    November 5, 2013

    @Blaine, really a nice Blog, my company, STMicroelectronics is working a lot on integrated  smart meter systems, I think it's a really challenging project that holds promises of great diffusion.

    END to END Security is a must in this kind of applications.


  8. eafpres
    November 5, 2013

    Hi etnapowers and thanks for your comment.  Can you describe a bit what you mean by End to End security?  I find people are very confused about security, especially in industrial settings.

  9. yalanand
    November 30, 2013

    @Baline, thanks for the post. I want to  ask one question after looking the meter design that what was  the need to use three processors, can't we incorporate all the things into one integrated chip.

  10. eafpres
    December 2, 2013

    Hi yalanand–My view is they are dividing up the functions to ensure reliability, reduce complexity for qualification, as well as leave open the potential to upgrade one section without affecting the rest.

    So you have an application processor which is a general purpose unit.  The security processor has hard-coded algorithms to allow fast encryption/decryption.  This could be done in the application processor but would consume a lot of resources and possibly reduce security.  Finally, the metering processor hard codes all the algorithms needed for the particular meter.  I guess the last one might change over time if new standards come into place, or perhaps it can be tailored for specific meter OEMs, but I'm not sure on that.

    The bottom line is I interpreted the design as being modular to reduce the risk of errors or malfunctions in the critical metering and security tasks.

  11. etnapowers
    January 7, 2014

    @Blaine, I refer to the cryptography for privacy and anti-hacking protection, enhancing the data security.

  12. Davidled
    January 7, 2014

    I think that secret key crypto through the digital signature would be a part of security algorithm. I believe that STMicroelectronics built the demo board related to smart meter to overcome the security issue.

  13. etnapowers
    January 7, 2014

    Yes DaeJ, I think you're correct. The  security algorithm is however very important to be implemented in the smart meter system, according to me, so I wanted to underline its importance.

  14. eafpres
    January 8, 2014

    @etnapowers–security for the entire power system is definitely important.  A consideration is information that could be derived from, say, knowing the power consumption signature of a home.  If the bad guys got access to all the smart meter data, they could develop the signatures, then easily detect when it is likely no one is home from looking at changes in the use profile.  This is just one of many examples where not only is data integrity essential, but privacy will be very important.

  15. etnapowers
    February 3, 2014

    @eafpres,I couldn't agree more on this point. The consumpion monitoring is one of the modes by which the bad guys could control the presence of someone in a house, another example is a house for holidays. If the bad guys know the energy consumpion of the house during one year they can know the right period to visit that house because they are sure that none is there. They could monitor the energy consumption of many houses in this way and organize their illegal activity based on this data.

  16. Victor Lorenzo
    February 3, 2014

    There are more subtle presence monitoring methods and one of them is WiFi/PLC network activity monitoring.

  17. eafpres
    February 4, 2014

    @Victor–You are correct; PLC (Power Line Communications) and WiFi and DSL etc. all have security but it depends on how it is implemented.   We can hope that the power companies getting data from our meters using PLC are using correct security, but we won't konw until something goes wrong.

    For WiFi, certainly the articles on the internet would tend to say a large fraction of home WiFi routers are not properly secured.  Are you aware of methods to monitor acivity over WiFi without actually snooping the data?  In other words, are you saying you could estimate data usage even with a properly secured WiFi router?

  18. Victor Lorenzo
    February 4, 2014

    In the case of PLC I'm not aware of readily available tools, but for WiFi/LAN/WAN penetration testing there are several Linux distributions containing all necessary tools. Probably the most popular is BackTrack Linux (now Kali Linux). It is officially a penetration testing environment and you can use it to test your network for robustness.

    It should be possible to monitor WiFi network bandwith usage and detect activity levels from some specific devices (mobile phone, tablet, notebook, etc). I made several tests at home a few years before with BackTrack Linux 4 and I was surprised with the results.

  19. etnapowers
    February 6, 2014

    Yes Victor, here you can find an interesting link on the subject you mentioned.

  20. Victor Lorenzo
    February 6, 2014

    @etnapowers, a few months ago we were internally discussing about a project similar to that depicted in the presentation. Of course this kind of tele-care application monitors presence, actions, movements and displacements for a good reason.


  21. etnapowers
    February 6, 2014

    @Victor: Absolutely correct! A tele-care application like that could save many lifes, it's a huge example of the IOT approach having the goal of the enhancement of people's safety. I hope thet you decided to further discuss about a project like this.

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