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Write enable does not go low with PROG32Z and SST39VF020 Flash
Andy S. May 15, 2014 at 11:49 AM (11:49 hours)
Staff: Takao Y.

  • Hello!
    I'm trying to program two SST39VF020 Flash chips with a Freescale MC68LK332 CPU through PROG32Z. I've downloaded the SST_39VF020_1x8x256k.32p algorithm and the SST_39VF020_2x8x256k.32p algorithm, and tried both. However, the Write enable pin on the flash memory does not go low and PROG32Z is unable to program. Also, if I try to erase the memory, write enable still does not go low, yet PROG32Z tells me the erase operation was successful. A read operation tells me that it is NOT successful. Any read operation seems to work fine, since write enable does not need to go low for those operations to work.

    I have tried other algorithms and I can see that write enable does go low, but the memory does not program. Write enable is tied to a 2.2K pullup, but seeing the pin pulled low with other algorithms has made me rule out the pullup as a cause for the problem.

    However, my application may be unique in that I am using 2 flash chips with shared 16-bit address lines, and each chip handles 8 bits of data. Do I need a custom algorithm for this to work? Or am I using the wrong algorithm? Or is it something else entirely? Any help is greatly appreciated!

    Andy Samuelson
    Pro-Dex OMS
    Beaverton, OR, USA


  • Greetings,

    I see that you have correctly created a custom algorithm request to get your issue resolved. I hope our algorithms engineers can get your problem resolved as soon as they can, however understand that we get many requests and it may take a week to get your custom algorithm created and tested.

    I will be setting this forum thread as resolved for now since there is nothing more to be added here in the public setting.

    Takao Yamada

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