What Microprocessor do I use?

Discussion in 'Embedded Systems and Microcontrollers' started by digielex, Jun 14, 2007.

  1. digielex

    Thread Starter Member

    May 21, 2007
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    0
    I have looked through previous threads on the topic of microprocessors and microcontrollers but am still a bit confused regarding the best microprocessor to go with for my application.

    My application needs to do 3 things
    1. Set the speed of a dc motor based on user input
    2. Set the temperature of a hotplate based on user input and use feedback to ensure the temperature remains constant
    3. Both speed and temperature must be displayed on an external lcd display
    4. Networking capability is desired though not mandatory

    I am not aware of which microprocessors are most preferred by designers these days. Any suggestions on which microprocessor I should use would be greatly appreciated.

    Thanks
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    They're all good. Your requirements do not suggest a useful metric for pairing down the field. It might be more useful to ask how long will it take to devleop the application, using what tools, and who will maintain the result after it's finished.
     
  3. digielex

    Thread Starter Member

    May 21, 2007
    16
    0
    Sure, I agree with you. However, time is not the constraint currently. The idea is to have a good microprocessor-based application (concern being the rate at which microprocessors are becoming obsolete)
    I want to use one that is definitely not going to be obsolete in the next 5years.
     
  4. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    You can use a microcontroler for that application. However, you can use also the Z80 processor from Zilog, since it is being used in a large number of applications and is in full production.
     
  5. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Keep in mind that if you decide to use the Z80, you will encounter the need for a number of support components such as PROM, RAM, and IO expansion devices. You will also need an A-to-D converter device.

    That is the advantage of using a microcontroller in that you do not have to implement these function in separate devices.

    Microchip and Atmel both have excellent and very inexpensive and in a number of cases free microcontroller software development tools for their microcontroller series.

    Whatever your choice, you can always inquire with the manufacturer if they foresee the discontinuance of a device. Tell them that you are looking for a device with a longevity of 5 years (or wahtever) and ask if the device is recommended for new designs with that constraint. I think they will be frank with you about the device's foreseable lifetime.

    hgmjr
     
  6. digielex

    Thread Starter Member

    May 21, 2007
    16
    0
    Thanks much! This is exactly what I was looking for.
     
  7. Papabravo

    Expert

    Feb 24, 2006
    10,135
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    The 8051 was introduced in 1978 and is still going strong
    Microchip had the 16C54 in the late 1970's and that family is still going strong.
    Freescale has the HC05 and HC08 families that have a considerable following.
    The Zilog Z8 has been around since the early 1980's.
    The Atmel-AVR is well into it's second decade

    Where do you get this idea that processors go away on short time scales -- from the PC market? Tch-Tch
     
  8. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
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    Does Moore's Law encourage the idea of obsolescence? Given the central role it plays in the semiconductor industry one could be forgive for thinking it does.

    Dave
     
  9. a_kent

    Active Member

    Jun 12, 2007
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    0
    Most microcontrollers do not suffer the same fate of the high end processors at anywhere near the same rate, thank God!!

    I have been through EOL's (end of life's) with many higher end processors.

    With microcontrollers (PIC, AVR, 8051 derivatives, etc.), most last a long time, as has been said.

    Also, when a device is EOL'd, they 'most of the time' will give you a chance to buy a lifetime supply. At that point in time, you must weigh the engineering costs of a new design vs. buying a billion of the old part.
    ===
    My best advice is to pick a part that you like, go to the mfg's website and see what it's status is. If they say it's EOL'd, then choose another.
    If they say 'full production', and you can buy in stock from the online distributors (Digikey, Mouser, etc.), then it's a pretty safe bet that it will be around for a LONG time.

    Popular parts don't die!

    Best,
    Kent
     
  10. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    Given the cost of developing new architectures and the tools that go with them you should rest easy in the knowledge that as has been observed popular parts just keep ticking in new, more varied, and faster implementations.

    So here's a series of questions. In your mind what is the most recent new 8-bit architecture? How long has it been around? How long do you think it will stay around?
     
  11. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
    4
    Maybe we need to differentiate between architectures and specific parts in considering obsolescence. Architectures rarely disappear, while specific parts do reach end-of-life.

    New architecture requires massive supporting tool chains and new set of experiences, from compilers to programmers and documentations and skills. It'd be mad for a company to throw away existing architecture and design a new one, especially for 8-bit designs where the differences would be pretty minimal.

    Advances in process technologies, circuit designs, etc. do ensure that no specific parts stay the same over a long time. They usually do have newer compatible drop-in replacements in microcontroller or embedded realms, unlike in high-end processors for desktops/servers where it is just not possible to create faster compatible parts for long due to the rapid advancement of speed. In this case Dave is right, I do think that Moore's Law encourage rapid obsolence in desktop/server arenas.
     
  12. digielex

    Thread Starter Member

    May 21, 2007
    16
    0
    I see this thread has come a long way ...

    Thanks for all your inputs. The sponsor for the project has asked me to go with MCF5282 ColdFire®, which I was researching a couple of days ago.

    Comments are welcome :)
     
  13. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
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