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Pickit 3 tips and ideas

Discussion in 'Microcontrollers' started by be80be, Mar 28, 2017.

  1. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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    Why do you have pull ups on PGD etc? I take it the chip isnt soldered into the board itself? Why not just take the chip out and bread board to program?? Now your gonna say you saved 2p on a socket and soldered in a chip arnt you.
     
  2. JonSea

    JonSea Well-Known Member

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    Once again, your facts are in error. The TAP-28 board does not have pullups on PortB.6 and PortB.7 unless you have bogged them in for some reason. In my designs, I try to keep the ICSP lines unburdened if at all possible.

    In fact, be80be's video in the original post in this thread shows a TAP-28 board programmed with a PICkit 3.

    schematic.png
     
  3. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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    I dont know now! I have the V 3.0.0 version, I found it the other night. But a quick searched suggests there is a newer version that has everything the old pk2 version had, like the logic analyzer etc.

    So I cant find the version I have but I found the newer one!

    http://www.microchip.com/forums/m739890.aspx

    The name changed so thats why it might not be well known, its called the pickit 3 scripting tool. I guess I have the beta version, I might have a go at the new version when I get a chance.
     
  4. dave

    Dave New Member

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  5. JonSea

    JonSea Well-Known Member

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    Regarding power, here is what the PICkit 3 documentation says. The PICkit 3 can supply 30mA, compared to 100mA for the '2.

    SmartSelectImage_2017-04-02-08-22-58.png

    Regarding MrDEB's panic about the pull-down resistors. The PICkit 3 documentation states:

    SmartSelectImage_2017-04-02-08-23-58.png

    These are in fact the same 4k7 pull-down resistors the PICkit 2 has. It was recently demonstrated in another MrDEB epic saga that a PICkit 2 programmed perfectly with 10k pullup resistors on PGC and PGD. The 24F-series chip in the PICkit 3 can source/sink less than the 18F2550 in the PICkit 2, but 10k pullups shouldn't cause any problems. Best practise is not to have any pullup resistors on the ICSP lines, but the real world may dictate otherwise. Here again, the facts don't support MrDEB's conclusions.
     
  6. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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    Might just be me, I dont use the PGD lines for anything but ISCP. IF I need the pins then I program the chip out of circuit, its a throw back to when I started and wanted to avoid any added mess ups. I just never got out of the habit. Having said that, I have never had a problem programming with the pk3. I brick mine when it swaps drivers.

    But again I 99% of the time used MPLAB to debug and program.
     
  7. JonSea

    JonSea Well-Known Member

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    When back when, I always used to remove the PIC for programming but when I got the PICkit 2 and saw how easy it is to do it in place....I've hardly done anything else.

    If you're using SMT, you're stuck with ICSP.
     
  8. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Because it's easier to run it all directly from MPLABX :D
     
  9. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Mostly you can happily use the ICSP lines as I/O as well as programming pins, I don't use hardware debugging so that's never a concern - you just need to apply a little common sense as to what you actually connect to the pins.
     
  10. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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    Yeah but some of us were born after the LED was invented :p.
    In circuit debugging was an excellent way to learn stuff for me. I am on the side of using a way bigger pic than you need, I also dont use one pic for all parts of a project.

    But then again I am hobby only, I dont have to think about BOM or how people will use a product etc, I have the luxury of doing it all for fun. So incubator, use a pic for heat and humidity and another for turning, then another for the fans control.......Network them together some way and you got an interesting project. Totally against good practice, but its a good way to learn and its stuff I make just for me mainly. The non pic stuff I tend to be more serious with because it costs alot more.
     
  11. MrDEB

    MrDEB Active Member

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    I stand corrected the tap28 has B4 & B5 for the pull up resistors.
     
  12. JonSea

    JonSea Well-Known Member

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    On the TAP-28 board, the LEDs and switches may be completely removed from the circuit by clearing solder jumpers for each.
     
  13. be80be

    be80be Well-Known Member

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    This is kind of off from where we started.
    I've used all 3 the app and MPLAB IPE and MPLAB X the problem I had and I no its the power and a 1 uF cap isn't the problem the red cap is a ,1uF I had to look I had 1000 of them in .1uF 1.0uF and 10 uF
    there 1% and come in a red box like you see.
    I programmed the Tap 28 with a 18f25k20 but at first it would shut the power off and the chip not run with any app.
    I no this because I used a red led with a 1k resistor across the power line. to watch it. Now I can program it with any app
    but it seems to be the best way is to power the target......
     
  14. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I refer you to what I've been saying right through this thread! :D

    Why would you not want to power it externally?, the TAP board shown above even has a USB socket for doing exactly that.
     
  15. be80be

    be80be Well-Known Member

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    It's a 3.3 volt chip usb not work
    I no what you said power the target That's what I'm doing
    Power from the pickit3 is ife at best and that's even with just a chip .
     
  16. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I did it for many years, having to unplug LCD's etc. while programming :D

    I've now got a little 9V battery in a box with a switch on it, and use that to power the target board. My target boards always have suitable regulators on them, so the 3.3V 24F board has both a 5V regulator and a 3.3V one - with the power to external boards selectable as 5V or 3.3V with a jumper.
     
  17. DirtyLude

    DirtyLude Well-Known Member

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    Usually I dedicate those pins to debugging as well, but recently I had to use one of the pins for both programming and GPIO. Ran around in circles trying to figure out how to do it as every manufacturer and chip I have used in the past that has alternate uses for pins requires you to set them. With the PIC, it's just use it as what you want to use it for and it will work and debugging will be disabled. Off topic, but it was weird.
     
  18. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

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    Because the IPE is exactly the same as that, I have used it a couple of times... It behaves the same as the standalone app... Remember LG.. The pickit3 has to change it's firmware every time a different device is inserted, Thats probably why the old standalone app is used... Too finiky.... The IPE seems to be a tad better...
     
  19. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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    I might try the IPE then, the changing of firmware is always a risk on my system! its a real PITA.
     
  20. MrDEB

    MrDEB Active Member

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    well my pickit2 got here today. That was fast!!
    now back to work.
     
  21. be80be

    be80be Well-Known Member

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    OK I got my nice power adapter Thanks Jon I like it. Next I hook the thing up set it for 3.3 volts guess what the pic18f25k20 still don't program. So here is the fix windows 10 doesn't like my toys LOL it will not let MPlab IPE load the files and Mpab IPE is dumb and tells you It did guess because it's it's files. I run the dang thing as administrator and guess what. Know more problems.
     

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