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Pickit3 not programming 100%

Discussion in 'Oshonsoft' started by camerart, Jun 13, 2017.

  1. camerart

    camerart Active Member

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    Hi,
    I am using a Pickit3 to program a PCB with an18LF2520 PIC and LCD using MPLAB, and in circuit programing.
    I have a 5V battery connected, passing through a 3.3V regulator.
    I've programmed it with a simple program, flashing LEDs with an input button, so the circuit is ok. The LCD show digits, but there are odd extra icons, and the lines are not correct.
    I've tried powering up using the battery and with external power settings. Also power from Pickit3. 3.3v and 5v (The PIC has a 2-5.5V range)
    Sometimes, MPLAB show, 'wrong PIC' plus other error, and doesn't connect.
    Any clues please?
    Camerart.
     
  2. Pommie

    Pommie Well-Known Member Most Helpful Member

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    From my experience, you can't power anything more than a single pic chip with the Pickit3. In fact, I'm not sure you can even power the pic. Keep it powered externally and check all your connections. Do you have anything else connected to the clk and dat pins?

    Mike.
     
    • Agree Agree x 1
  3. camerart

    camerart Active Member

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    Hi M,
    True! I first tried it (one PIC) powered from Pickit3 and it worked for a while. since I've added an LCD it is less likely to work.
    CLK and DAT pins connected to LCD DATA.
    You've reminded me about a previous similar problem, and the remedy was to add a resistor to one of those pins, I'll have a dig.
    C.
     
  4. dave

    Dave New Member

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  5. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    ONLINE

    As for the PK3, its power capability is very low as Pommie said. How low? It is really not in the specifications last time I looked, but I have read it is about 20 mA.

    For your LCD, are you sure it is not the program? Is it parallel or serial? If parallel, are you using fixed waits after toggling E or monitoring the busy flag? I have gotten odd characters when timing is off. There is also a prescribed power-on-reset protocol that should be followed for either serial or parallel LCD's.

    John
     
  6. camerart

    camerart Active Member

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    20mA! I wonder why they offer power from PK3 at all? It's simply going to fail.
    I'll leave the LCD suggestion, for now, as I doubt is't that, but thanks.
    See next post.
    C.
     
  7. camerart

    camerart Active Member

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    Hi Both,
    I found the previous above mentioned remedy, it was a 10K resistor between PGM and GND. Previously I made up a ZIF programming socket with power ON/OFF complete with 10K resistor, plus extras. I just tried a different PIC on the ZIF socket, powered externally, and this failed too.
    What appears to be the common denominator, is PICKIT3 and WINDOWS10. I tried the compatibility settings, but still no good.
    C.
     
  8. camerart

    camerart Active Member

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    Hi,
    I've been playing around with many combinations of tests. Note, this is a new Windows10 installation! I have two PCBs to test.

    I found an uninstalled PICKIT3 programmer, and clicked the .EXE, and it opened. This programs with no external power (LCD unplugged) Previously the PICKIT3 programmer stopped, and I switched to MPLAB, after suggestions.

    I also found that the Config settings were incorrect for one of the PCBs, this was corrected and saved in the config settings.

    All a bit of a mystery, but I'll carry on playing.
    Thanks, C.
     
  9. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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  10. camerart

    camerart Active Member

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    Hi E,
    They are having a similar set of problems to me.
    These kind of problems can appear at anytime, it seems, but once ironed out, they seem to disappear for no reason. It also happened with my Velleman board, and extra wires seemed to fix it.
    I am finding that the config settings are mysteriously being changed also.
    I am able to program if, once I get a problem switch between the PICKIT3 programmer and MPLAB.
    Thanks, C.
     

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