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Need help: 18f27K42 vs 18f25k42

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ag70
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2018/07/27 10:12:02 (permalink)
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Need help: 18f27K42 vs 18f25k42

Hi. I have a problem in usage of E2ROM and FLASH, maybe somebody knows solution.
I have transferred old project from 18f25k22 to 18f25k42. And this change was 100% successfull. Everything works like before.
In next step I used 18f27k42. Difference between 18f27k42 and 18f25k42 is only in memory size (RAM, EEPROM, FLASH). And some settings which are result of these differences. In my opinion, of course.
BUT the same program with 18f27k42 does not work properly about self re-programming of FLASH. And propably EEPROM either. Part of data is memorized in memory, part not. For example when filling FLASH, 64 bytes are writing properly and next 64 b are empty, and so on.
In previous family (k22) and earlier families I have NEVER similar problems. Members of the same family never have any mechanism working different. I mean, to this time using of "bigger" member of the family was problemless. Of course I remember about registers for addressing of higher parts of the memory.
Maybe I missed any info in PDF? Is usage of re-writable ROM in 18f27K42 different than in 18f25k42 ???
 

my config today: Dell Optiflex i7 4-core, win7 prof x64, 12GB RAM, SSD, Mplab X 4.10 (or 4.20 but only if necessary) + ICD4, PIC18F27K42, assembly only

7 Replies Related Threads

    qɥb
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/27 16:29:36 (permalink)
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    The PIC18F25K42 and the PIC18F27K42 are documented in separate datasheets.
    That should have been a red flag, if the only difference was memory size, they would have been in the same datasheet.
     
    Have you compared
    TABLE 15-2: FLASH MEMORY ORGANIZATION BY DEVICE
    from the 25K42 datasheet with
    TABLE 5-4: DEVICE CONFIGURATION INFORMATION FOR PIC18F(L)F26/27/45/55/46/47/56/57K42
    from the 27K42 datasheet?

    This forum is mis-configured so it only works correctly if you access it via https protocol.
    The Microchip website links to it using http protocol. Will they ever catch on?
    PicForum "it just works"
    ag70
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/27 17:09:54 (permalink)
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    I know this. But 25k42 was delivered to the market earlier and his number is included in compaprison table inside 27K42 datasheet. So I expected, that both circuits are the same family "k42".
    But they are NOT. And this is a solution.
    Erase row in 27k42 is 2 times bigger than in 25k42 (and 25k22). And this is main difference between these processors, propably.
    Solved.

    my config today: Dell Optiflex i7 4-core, win7 prof x64, 12GB RAM, SSD, Mplab X 4.10 (or 4.20 but only if necessary) + ICD4, PIC18F27K42, assembly only
    mbrowning
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/27 17:40:49 (permalink)
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    K22 is exactly the same. 7k22 parts have a larger row size.
    DarioG
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/27 21:54:39 (permalink)
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    funny, I can't click on stars in this thread

    GENOVA :D :D ! GODO
    qɥb
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/27 22:22:51 (permalink)
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    DarioG
    funny, I can't click on stars in this thread

    Me neither. I suspect it's a setting for this whole "[Training Discussion Group] » MCU2101 - Getting Started with PIC18 Architecture and Instruction Set" forum, which is rarely used so we don't notice it often.

    This forum is mis-configured so it only works correctly if you access it via https protocol.
    The Microchip website links to it using http protocol. Will they ever catch on?
    PicForum "it just works"
    DarioG
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/28 02:16:10 (permalink)
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    Yes, I assumed the same. a funny subforum as well :)

    GENOVA :D :D ! GODO
    ag70
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    Re: Need help: 18f27K42 vs 18f25k42 2018/07/28 05:08:11 (permalink)
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    mbrowningK22 is exactly the same. 7k22 parts have a larger row size.
    Right. But see, that all 2xK22/4xK22 have much more differences compared to 6xK22/8xK22. So these families are not only described in separate PDF's but also are no connected together another way.

    In manual "PIC18(L)F26/27/45/46/47/55/56/57K42" in comparison table exists PIC18(L)F24/25K42 like a FAMILY MEMBERS. And this should NOT be made. Because is NOT possible to move any software without relatively big modifications.
    Additionally in this PDF you can find many errors in FLASH operating description, because it looks to be copy-paste from PIC18(L)F24/25K42 without expected modifications.
    That's why I expected, that these processors are "the same".
    post edited by ag70 - 2018/07/28 05:11:25

    my config today: Dell Optiflex i7 4-core, win7 prof x64, 12GB RAM, SSD, Mplab X 4.10 (or 4.20 but only if necessary) + ICD4, PIC18F27K42, assembly only
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