Searching for lower power microcontroller

Discussion in 'Embedded Systems and Microcontrollers' started by Camz, Feb 15, 2010.

  1. Camz

    Thread Starter New Member

    Feb 15, 2010
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    Hello. I am currently working on a project using an Atom 40-m microcontroller with PIC16F882 processor. I am looking at ways to limit power consumption.

    Basically I have a pressure transmitter that needs to monitor pressure in a line at all times(can't put mcu to sleep for more than a few seconds) and report to the mcu in order to shut/open valve.

    In the cloudy months the solar panel has trouble keeping the battery powered for long periods so I am looking for powersaving techniques or a new design altogether(new microcontroller) in order to combat this problem.

    Is this processor a good one for this type of application or is there one which consumes less power that I should know about?

    Thanks,
     
  2. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
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  3. Markd77

    Senior Member

    Sep 7, 2009
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    There are a lot of power reducing methods, but the most obvious are reducing the voltage and frequency the chip is running at. Apparently at 2V and with the LFINTOSC it consumes 10uA which would probably run for years on a watch battery. If you need more frequency accuracy you could use an external 32.768KHZ crystal.
    Sleep mode uses even less.
    Your sensor probably uses much more than that - if possible the sensor could be powered by a MOSFET controlled by the MCU only when required.
     
  4. Markd77

    Senior Member

    Sep 7, 2009
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    Just looked at the atom datasheet and it runs at 20MHz 5V and there doesn't seem to be any way to reduce it. It somehow manages to use 10mA in sleep mode which is 1000 times more than the PIC16F882.
    Otherwise the Atom seems very good, but you might have to avoid it for low power applications.
     
  5. Papabravo

    Expert

    Feb 24, 2006
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    Checkout the TI(Texas Instruments) MSP430 series. They have multiple clock and oscillator arrangements that can be varied on the fly. There is certainly something there that will meet your needs. One more thing: the development tools are gcc based and absolutely FREE
     
  6. symqwerty

    Member

    Feb 22, 2010
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    Microchip claim that they have "Extreme" low power microcontroller. You can give a try.
    Try to look for CMOS or lvttl based device. As far as i know, it consume less power but that is just a theory and depend on product.

    Anyway, do you really need to use microcontroller in ur design? Is it possible to replace microcontroller with any 'logic' circuitry?
     
  7. Hulk

    New Member

    Jan 12, 2010
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    you are right these MSP430 are very good micros... I guess they have not been beaten on power cunsumption yet! 0.2mA/MHz
    A bit expensive though

    So basically to save power reduce clock speed and power supply voltage to up to 1.8V
     
  8. Camz

    Thread Starter New Member

    Feb 15, 2010
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    My main decision was whether to go with TI MSP430 or Microchip's XLP line. From my research the TI beats it pretty significantly in power efficiency.

    Yes I do need a MCU for this; I am using a LCD screen for UI and need to store settings in memory, etc...
     
  9. Camz

    Thread Starter New Member

    Feb 15, 2010
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    Thanks for the advice guys, looks like I will be moving along with the TI MSP430.
     
  10. Camz

    Thread Starter New Member

    Feb 15, 2010
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    Anyone have experience with the TI Code Composer Studio?
     
  11. Papabravo

    Expert

    Feb 24, 2006
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    @Camz
    I have no experience with TI Composer Studio
    The development board was #MSP-FET430U64.
    It included a USB connection to the PC with a JTAG connector to the proto board. The proto board had a ZIF socket to program parts.
    There was an LED or two and a some connectors so the programmer could be used a daughter board in a system.
     
  12. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    first you need to express your sensors power requirements in comparision to the controller. It may make more sense to decrease the larger consumer.

    Sleeping your controller even for a couple of seconds will realize huge power savings compared to continous running. Depending on your sensors power up time, you may be able to power that down for some percentage of the period as well
     
  13. Camz

    Thread Starter New Member

    Feb 15, 2010
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    GetDeviceInfo,

    We definitely took those things into consideration for our current product and made appropriate changes. We're moving further along in the development of new products and thin that the MSP430 series is what we want to work with.

    PapaBravo,

    If you didn't use CCS, what developming environment did you work in? The GCC-based programs?

    Thanks All

    I ordered that dev kit w/Jtag yesterday and have been fooling around a bit with the CCS IDE.
     
    Last edited: Feb 26, 2010
  14. Papabravo

    Expert

    Feb 24, 2006
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    Yes I used the gcc tools and was able to use a USB to JTAG adapter to download programs into a part in a ZIF socket on the development board. The design of the JTAG connector was easy to add to my PC board so I could duplicate that function on the production board.
     
  15. Hulk

    New Member

    Jan 12, 2010
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    Code Composer Studio worked with me very well at the beginning but after the 1 month trial expired... After that I switched to the IAR compiler (much more stable and simpler)
     
  16. Camz

    Thread Starter New Member

    Feb 15, 2010
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    Yea I've been fooling around a bit with CCS today and it's a bit confusing. I downloaded IAR embedded workbench earlier today too so I may follow your lead and just start using that instead.
     
  17. Camz

    Thread Starter New Member

    Feb 15, 2010
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    So I found the company Sourbaugh and their developmental boards for the processor I chose. One thing though, there was this message from the owner on the website. I bolded what I'm concerned with at the bottom:

    [​IMG]

    Dear Customers,

    On 10 November, 2008, we were informed that TI had delisted SoftBaugh as an MSP430 tools vendor on their third-party site. Ostensibly, we have caused significant "consternation" among their ranks as we explore the benefits of Cortex-M3 processsors, such as the STM32.

    Much of this rankle probably stems from our forthcoming book, "Porting Your Green MSP430 Design to the STM32". We believe that while a small portion of MSP430 designs genuinely require that part, approximately 80% to 90% of the MSP430 applications we've seen over the last ten years are better done by more modern processors such as the STM32. Back in the summer of 2008, we made numerous offers for TI to review and rebut the assertions we make in this text, but all of these offers were either ignored or declined outright. One might imagine that, by refusing our offers to rebut, TI thinks that the material is harmless. On the other hand, by delisting us TI might be assumed to now be trying to bury our point of view. This, to us, is a strange action since they haven't even bothered to read it, which might make one believe that they already know what the weaknesses are and see no choice but to hide.

    For their part, the ST Micro response to our material, especially the parts where I beat on them, has been uniformly cooperative. You will soon see additions to their product line that reflect, to some small degree, the influence this material has already made, even before it has been published.

    This behavior leads me to wonder about the relative quality of support a customer might experience after making a buying decision. Does the chip vendor hide and obfuscate, resorting to petulance when all bluster fails? Or do they see themselves as a partner in your success?

    Of course, people, organizations, products and services all change over time. One company or product that is great today may need judicious and enthusiastic application of the bludgeon of truth tomorrow. We'll see. But for now, I'm calling this situation as I see it today.

    The great thing about the marketplace in our global economy is that I don't have to be able to convince you or anyone else that most MSP430 customers are better served by the STM32 or other parts. I only have to be right. The evolutionary forces of the marketplace will take care of the rest. The deluded, meaning those easily swayed by clever marketing, will eventually suffer loss of business or an inordinate drain of resources, while the clear-thinking will be more efficient and prosper. It is that simple. As for me, for purely selfish reasons, meaning that I make more money when I help my customers succeed and I make less when they don't, I want my customer base to be in the group that prospers!

    Our business has never been built around just selling tools. Anyone can do that. Look at all the vendors out there that basically sell you a piece of green and that's it, you're on your own so sink or swim. Instead, our goal has always been to help you make great design and business decisions. In addition to just tools, our educational material, books, consulting services and lectures and on-site seminars have all been targeted at helping you make better decisions by giving you a hilltop view that is inaccessible otherwise. Viewed that way, we're surprised it took TI so long! Perhaps they imagined us to be waiting for our crumb.

    Their action, then, marks their recognition of our increasingly influential role as a source for opinion and insight, and for that we thank them.

    Best wishes,

    Tom Baugh
    President
    SoftBaugh, Inc.

    Update, 15 May 2009

    Yesterday TI announced that they were acquiring Luminary Micro, a competitor to ST Micro and their STM32, in order to offer Cortex-M3 parts to their customers. Apparently, TI has signed on to the concept that the MSP430 is lacking and doesn't fully serve the needs of their low-power customers. Glad I could help, despite their arm-twisting to try to silence my message.

    The lesson? Run from the MSP430 as fast as you can. Now, it seems as if even TI agrees with me. But don't forget, the same company that monkeyed with the MSP430 is now making ARM chips to respond to the gaping hole that I pointed out, a message they tried to suppress. The MSP430 once was a great processor before it was twisted into uselessness after it seemed you were captive. What do you think will happen to the Luminary Micro parts over time? Do you want to bet your company on that?

    Of course, this is just my opinion, but look at my track record and come to your own conclusions.

    So what does this mean? The MPS430 is crap? Should I go with an STI processor? Anyone have anything bad to say about the MPS430 series?
     
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