Write EEPROM with Interrupts


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  1. #1
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    Question Write EEPROM with Interrupts

    I am getting closer to the testing stage of my project but have one question. In the PBP manual it says that if interrupts are used the following define should be used.

    DEFINE WRITE_INT 1

    further in the code I have a sequence of writes, four in a row like below,

    write Degrees_up, word vdegrees_up
    write Degrees_10, word vdegrees_10
    write Degrees_20, word vdegrees_20
    write Degrees_30, word vdegrees_30
    .
    .
    rest of code

    If I am reading the manual correctly, the define statement will mask and unmask the interrupts while the write is occurring. Is this correct?

    Thanks for any clarification you can provide.

    Zapman

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    Default Re: Write EEPROM with Interrupts

    First, you don't mention which PIC you're using. Newer ones have a NVM Interrupt that can be used to set an interrupt when done writing to the EEPROM. Older ones need the GIE disabled when writing to the EEPROM. This might be a start.

  3. #3
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    Red face Re: Write EEPROM with Interrupts

    Sorry I didn't mention the chip. It is a PIC18F45K80. I was asking because the PBP manual talks about needing to mask the interrupts during EEPROM writes. I am using DT's interrupt handling software and have modified it for the K80. My real question is do I use the Define statement to handle masking the interrupts during EEPROM writes?

    Thanks

  4. #4
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    Default Re: Write EEPROM with Interrupts

    If in your design, an interrupt can occur during EEPROM write, then use GIE bit to disable temporary all interrupts. After WRITE enable GIE again. Thats all.

    Ioannis

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    Default Re: Write EEPROM with Interrupts

    If you use 'DEFINE WRITE_INT 1' then the library code will disable interrupts around the unlock and setting EECON1.WR to initiate the write operation, but unlike the sequence shown in most datasheets it will reenable them before the write operation is completed.

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    Default Re: Write EEPROM with Interrupts

    That"s right, DEFINE WRITE_INT 1 is all that you need. I have used it for about 7 years with out any problems. I used to use Ioannis way at first and it worked as well.

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    Thumbs up Re: Write EEPROM with Interrupts

    Quote Originally Posted by DaveP View Post
    That"s right, DEFINE WRITE_INT 1 is all that you need. I have used it for about 7 years with out any problems. I used to use Ioannis way at first and it worked as well.
    Thanks for the answer! I sometimes find small snippets or statements in the manual that leave me wondering about the actual functioning. In this case it was the DEFINE WRITE_INT 1. I found it mentioned but didn't see the explanation about how it worked. Thanks again to all. I can get back to programming now... maybe after another cup of coffee!

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