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Help needed desperately with PIC LCF meter

Discussion in 'General Electronics Chat' started by bigal_scorpio, May 2, 2008.

  1. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    Hi Al,
    Look here:
    This works OK, you can either use the Oshonsoft software or Nigels parallel prommer software.

    http://www.oshonsoft.com/picprog.html

    Drop 'Wombweller' a PM he is using one.:)
     
  2. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Lots of people using the PICkit2 and my Junebug with some success.

    If your a DIY I'm clearing out my orginal Inchworm (ICD2 compatible) PCBs for cheap.
     
  3. bigal_scorpio

    bigal_scorpio Active Member

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    Finally getting somewhere!

    Hi guys,

    Well at last I have got my programmer working! Win Pic seems to do the trick, and programs my 628A with no problem. :) Thanks Picasm.

    Now the bad news, thanks to Eric's code I was able to see if there was any output to the LCD and sadly there isn't, so I have a problem somewhere.

    I have even breadboarded the PIC to an LCD and the same result - no characters - just the blocks!

    Now at least I have narrowed down the problem a bit, it surely must be something to do with the LCD connections, so I am going back to the datasheets for them to see if there is anything wrong - my god these straws are hard to clutch at hehehe.

    Anyway thankyou to you all who have participated so far and allowed me to at least keep my sanity, if not my hair! hehehehe

    I will keep updating the thread as I progress in case maybe someone in the future will get the same problem as this or maybe the same LCD screens.

    Just a thought but could the fact that the design calls for a 2 x 16 LCD and mine are 2 x 20 be causing my grief, though I have also tried a 1 x 8 LCD though neither came with a datasheet, the connections seem fairly standard on LCDs or I hope so after all this trouble!

    Thanks again folks, I don't know what I'de do without the help!

    ...............Al
     
  4. dave

    Dave New Member

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  5. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi Al,
    If you get to the point that you decide to use the LCF project as a 'door stop', pop the whole thing in the post to me,
    I'll have a look.. you have my address.:)
     
  6. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Al,

    Have you run Erick's code that changes the value of a single pin. I seen where you said it seemed to run away. Did it toggle the pin?

    Maybe build some other tools first?

    A programmer with ICD would a good tool for debugging. You could set breakpoints inside the LCD code and check the state of each line with a volt meter or a logic probe.

    For 16F work a serial ICD2 is fast enough. Bill is closing out the the Inchworms ICD2's so the price is right. They are mostly a 16F877A, a few transistors, and a handful of resistors and caps. Uses code from Microchip's ICD2 so it will work with MPLAB as long as Microchip supports the ICD2.

    A PICkit2 or Bills clone the Junebug is even better. It runs at USB speed and does double duty as a 3 channel logic analyzer. That would be nice for looking at the LCD control lines on the current project. 3 lines is not much but you would be suprised what you can do with it.

    Peter Anderson has a PIC programed as a logic prob for under $3.
    Or you can build an Mondo SuperProge which has 17 or 18 functions including LC. These use a 4 char 7 seg LED display.
     
  7. bigal_scorpio

    bigal_scorpio Active Member

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    Hi Eric,

    I may just do that if it doesn't end up being "embedded" in a wall somewhere. hehehe

    Al :)
     
  8. bigal_scorpio

    bigal_scorpio Active Member

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    Hi 3v0,

    Some of that stuff sounds very interesting and probably is to many other members. How about some links to the projects?

    As to the toggling pin, yes, but see my other posts, the LCD now seems likely suspect!

    Regards...........Al :)
     
  9. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Last edited: May 6, 2008
  10. Kryten

    Kryten New Member

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    One more thing I noticed in the schematic is that it has (omly) four pin for programming (mlcr-vss-pgd-pgc). Are you shure that you are connecting the PIC correctly?

    Its worth checking. (also check that the crystal are installed correct with the right caps and stuff, I have made that mistake myself)
     
  11. bigal_scorpio

    bigal_scorpio Active Member

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    Sorted at last!

    Hi Guys,

    Glad to say its sorted out at last!

    It was finally Eric who said was I connecting R/W to ground!

    No I wasn't, DOH! I followed the actual drawing and there is no connection for R/W but Eric spotted it on the schematic, I bet the damn thing was working OK days before I found out! hehehe Electronics eh!

    Thanks again to all for the help..............Al

    BTW the meter is superb and if you don't have one I would recommend building this one! Just don't forget to ground R/W :eek:
     
  12. mrx23

    mrx23 New Member

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    Firmware

    Could someone upload a working compiled firmware (.HEX) for the PIC16F628A which is based on the newest LCFmet790.asm firmware?

    (newest firmware)

    Thank you!
     
  13. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Are you just wanting the hex file, rather than the asm source code.?
     
  14. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    The hex file is attached, had to use the '.txt' extension to get it uploaded, just change it back to '.hex'.

    This is the 628A version.
     
    Last edited: Jul 7, 2008
  15. mvs sarma

    mvs sarma Well-Known Member

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    I tried to make a zip file of all the relevant files derived using MPlab.
     
    Last edited: Jul 7, 2008
  16. mrx23

    mrx23 New Member

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    Thank you for the code!
    Have you build this LCF meter with 628A?
     
  17. bigal_scorpio

    bigal_scorpio Active Member

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    Hi to all,

    Just to confirm that I have built the meter with the 628A, and it works fine!

    But don't make the same mistake I did, make sure you ground the R/W pin on the LCD, which is only obvious in the schematic and NOT obvious on the circuit drawing....DOH!

    But thanks to the help from this forum, especially Eric, it worked in the end and is the best thing I have ever built, now I can use all those chokes that are in my bits box but had no markings! :)

    Al. (bigal_scorpio) :D
     
  18. mrx23

    mrx23 New Member

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    So you don't have the "CAPICATOR TIME OUT" hanging at startup?

    Did you use the modification (correction) for the schematic from here?
    P.E. LCF Meter Modifications

    How accurate is this LCF meter at high capacities? Like >1000uF

    Thx
     
    Last edited: May 26, 2008
  19. bigal_scorpio

    bigal_scorpio Active Member

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    Meter readings

    Hi mrx23,

    Yes I have the hangup, but I found a way round it, I turn on the meter in L mode and then switch to C and it works ok then, have you found a different way of preventing the hangup?

    As to the measurements of large caps I have measured quite a few 3300uF and they were within 50 in every case, except one which I new was faulty (swelled top) and that measured 150uF hehehe.

    I was more interested in chokes when I built the meter, as I mentioned I have a lot of them that are not marked and never been able to measure before, now I have them all measured and marked up, which will save me a good bit of cash as before I always had to buy them for different projects, and its not just the cost of the components its the cost of postage and the hassle of having to wait for them coming ;)

    Anyway if you need to discuss anything further or have any tips for the meter feel free.

    Regards.........Al :)

    BTW if you want to see some really weird cap readings look in an old Grundig Sky Digibox, or an Amstrad 400! I measured a duff 10uF from an Amstrad that thought it was 1200uF - still trying to figure out how a cap can fail and get a bigger capacitance! :confused:
     
  20. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    As it measures how long it takes to charge, presumably the capacitor was leaking, so took longer to charge?.

    But you're using the wrong device, you want an ESR meter to check electrolytic capacitors, measuring the value is rarely of much help.

    I've recently started using a Peak ESR meter, these read both capacitance and ESR - as expected, mostly the capacitance is in tolerance, and the ESR is far too high.
     
  21. bigal_scorpio

    bigal_scorpio Active Member

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    Hi Nigel,

    Peak ESR meters look good but a bit pricy for my budget. I just bet someone who was good with electronics and especially Pics could come up with a design for a homebrew one ;) Hint Hint

    All the best..........Al
     

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