HELP: How To RESET a CPU (MC68336) & Another Question

Discussion in 'Embedded Systems and Microcontrollers' started by SaMirakle, Mar 6, 2012.

  1. SaMirakle

    Thread Starter New Member

    Mar 6, 2012
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    Hi everyone,

    I'm new to this forum and I don't have any electrical engineering course background but I've been working with circuit boards for a bit now.

    Anyway, I have a question regarding a Freescale microprocessor: (MC68336 series. User's manual can be found here: http://cache.freescale.com/files/microcontrollers/doc/data_sheet/MC683336_376UM_ZIP.zip)

    Apparently, this processor has an SRAM standby mode. On the specific board I'm working on the SRAM and the SRAM Standby pin on the CPU is powered by a battery which has gone dead. Since the battery has died obviously the SRAM contents have been removed I'm assuming.

    My question is: How can I revive this board? It doesn't make sense to simply replace the SRAM with new ones because theoretically the new ones would be blank as well.

    Would I need to utilize the RESET function on the processor? If so, how do I even go about doing that?? :confused:

    Sorry if this is an amateur questions but everyone has to start somewhere!

    Thank you so much in advance. I'm hoping this community will be able to help me out!
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Ouch... that's a lot of files, but START.pdf was a likely place to start. However, it looks like the main processor specs. Is this a development board you have? If so, do you have a link to that? I wonder if just replacing the battery and powering the thing up will result in happiness. It has lost the last state data, but when the thing was first turned on it should have been in a similar state and thus should have some code to deal with this condition.

    That's off the top of my head, I don't use any Freescale products.

    Remember this: the only bad question is the one you don't ask. And welcome to the forums!
     
  3. SaMirakle

    Thread Starter New Member

    Mar 6, 2012
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    0
    Hey Ernie!

    Okay well I don't know what else you'd need but here's the product page link: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC68336

    As for replacing the battery, I've already tried that a long time ago and I've done it on multiple boards. Umm it's not a development board. It's actually an ECM (engine control module) board. I do know that it supports BDM (background debugging mode) programming but I don't have a BDM programmer yet (might end up buying one if I can't figure out how to restore communication since the SRAM lost power for a period of time).

    Any other thoughts on how to bring this back to life? Power flows through it but the communication pins are not pulsing with voltage which means it's not getting any communication power and my diagnostic software won't detect the ECM.
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Sorry I don't have any more advice. True you know the processor on this board, but that is just one component of many. An ECM is a tight little design with numerous requirements and sensors for it to work correctly and not something I can guess at making work. Wish I had more help or a direction but I don't.

    However, if the mods notice this thread, and since we don't support automotive modifications (which this sure sounds like) they might lock the thread, and they typically give some links that may be useful to you. The links may also be in the first sticky post in the "General Electronics Chat" area.
     
  5. Georacer

    Moderator

    Nov 25, 2009
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