Writing & Reading 2 Bytes to/from Flash


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  1. #1
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    I have looked high and low but cannot see where this is set.
    What exactly is this called and where can I find it?

    (I have the U2 Programmer with version 4.51.)
    Last edited by Zebryk; - 17th May 2015 at 00:17. Reason: Additional Info

  2. #2
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    its in the hardware configuration registers (fuse settings)

    WPFP = PAGE_0
    WPCFG = OFF
    WPDIS = OFF
    WPEND = PAGE_WPFP
    shown here with default pbp values (no code protection )
    it does help if you post you whole code (in code tags) not just snippets, and include what version of pbp used

  3. #3
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    Richard,

    I tried your suggestion but it did not work.
    As my whole code is >73,000 characters it will not post.
    I am using PBPX 3.0.7.4
    The PIC is a PIC18F27J13.

    Is my syntax / technique correct?

    Thanks,

  4. #4
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    what syntax ? at no stage have you posted the relevant config fuse settings you have employed.

    why not make a small pgm to test the idea

  5. #5
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    Richard is asking about config settings where watchdog timer, crystal mode, write protect, etc are all set, and what you are doing there.
    The program looks right to me tho I have not used it. Except the output doesn’t absolutely verify what was written, only what read back.

    Code:
    verifya var type ' byte or word
    verifyb var type '
    verified var bit '
    
    EraseCode $1800 ' Whole Block of 4 Words $1800 to $1864?
    EraseCode $1900
    RadioID = RadioID + 1
    RadioCH = RadioCH + 1
    WriteCode $1803, RadioID ' Writes to 4th Word in Block
    WriteCode $1903, RadioCH
    
    ReadCode $1803, verifya ' Reads from 4th Word in Block
    ReadCode $1903, verifyb
    
    verify = 1
    if verifya != RadioID then verified = 0
    if verifyb != RadioCh then verified = 0
    
    if verify = 1 then
    hserout2["RadioID: ", dec RadioID, 13,10]
    hserout2["RadioCH: ", dec RadioCH, 13,10]
    else
    hserout2[“It’s broken :(",13,10]
    endif

  6. #6
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    Each PIC controller has different page size that you can WRITE to.

    For example if your chip has 64 words page, then you have to read all 64 words, change what you want, then write back the whole 64 words page.

    It is a bit clumsy but that is how it works. You cannot change only the words you really want. And if you write less tat the page size, then data will not be written!

    So, my suggestion is to make an array, get the page form Flash, make the changes, then store back to Flash the array.

    Ioannis

  7. #7
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    Or, if reading/writing to a whole page of flash program memory does not appeal to you.
    You can always switch to a PIC model that has internally EEPROM or add an external Serial EEPROM.

    Regards,
    TABSoft

  8. #8
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    Default Re: Writing & Reading 2 Bytes to/from Flash

    Ioannis,

    This is getting more complicated than I figured.
    Might you be available to implement this for a fee?
    I can send you money in advance via PayPal.

    Thanks,

    Jay Zebryk
    Zebryk Engineering
    Southbridge, Massachusetts

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