Programming voltage on 8-bit PIC microcontrollers

Discussion in 'Embedded Systems and Microcontrollers' started by davidc, Jul 16, 2011.

  1. davidc

    Thread Starter Member

    Jul 2, 2009
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    I know that the programming voltage on some of the more recent PIC microcontrollers is 12V - and that charge pumps such as the MAX662 can be used to provide this from a 5V supply. But on some of the older PICs the programming voltage is 13V, right? Is there any standard IC charge pump that delivers this voltage?

    I have been using a JDM-style programmer and it's working fine - but I can't use it with my laptop because it doesn't have a serial port.
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    As far as I know the PICXXF does not need a high voltage to program them.
    The PICXXC (OTP) version will probably need the higher voltage.
    These can be programmed only ONCE.
    Better look at the datasheets of the pics to be sure.

    Bertus
     
  3. t06afre

    AAC Fanatic!

    May 11, 2009
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    I would suggest you get a PICKIT 2 or 3. They use USB and work without any problems. You can get PICKIT 2 clones quite cheap.
     
  4. AlexR

    Well-Known Member

    Jan 16, 2008
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    Older PICs require Vpp to be between 12Volt and 14Volt hence the usual 13Volt Vpp, the new PICs specify Vpp(min) is Vdd+4Volt and Vpp(max) is 12.5 Volt, so if your Vpp is between 12 and 12.5 volt it should be fine for both old and new series chips.

    Having said that however I agree with t06afre and suggest you save yourself a lot of hassle and get a PICkit2 or PICkit3 programmer.
     
  5. davidc

    Thread Starter Member

    Jul 2, 2009
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    Thanks for the feedback folks. I think you're right ... A PICKit is probably the most sensible option.

    @AlexR: That answers my original question - thank you.

    @bertus: I think you're right yes. Also, if I use LVP (Low Voltage Programming) mode - I furthermore lose one of the output pins IIRC.
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    A USB to RS-232 converter will solve the Laptop issue for using that programmer. I picked one up years back for cheap and it still gets some use even on PCs with serial ports, as the USB ports are on my front panel.

    However, Pickits are also debuggers so are well worth the investment (says the guy who owns 3 of em plus an ICD3).
     
  7. t06afre

    AAC Fanatic!

    May 11, 2009
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    A USB to serial converter may not work well with a JDM type programmer. I would not put any money in a new one. If you only will use it for your JDM programmer.
     
  8. davidc

    Thread Starter Member

    Jul 2, 2009
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    Incidentally, I actually have a usb-to-serial converter already, but hadn't tried it with my JDM programmer yet - as I had researched it previously and had gathered that it wouldn't work (that was before I got my JDM programmer working).

    You've reminded me to try it though Ernie. If it fails, I'll just look into a PIC Kit.
     
  9. davidc

    Thread Starter Member

    Jul 2, 2009
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    Just to update ...

    The usb-to-serial adaptor isn't yielding success on my desktop PC (if it's not working on the desktop, I guess it's not going to work with my laptop). This is using picprog 1.9.0 on a Debian GNU/LInux PC.

    I can't remember the specific picprog error, but will post it here if I have time. No big deal - I didn't expect it to work anyway.
     
  10. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    It's not a "standard IC" but there is a circuit I designed years ago (back in the days when people used to build their own programmers) that only needs 2 common transistors and produces 13.3v regulated from 5v input;
    http://www.romanblack.com/smps/conv.htm
     
  11. davidc

    Thread Starter Member

    Jul 2, 2009
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    I'm in transit at the moment Roman, but I hope to build your circuit once I have time (and maybe simulate it in the meantime). Thanks.

    On a related note, I discovered two open-source USB programmers earlier today:

    Time and circumstances permitting, I would like to try building one of these before buying a PICkit. They both seem to provide controller software for linux (which is vital for me). Anyone have experience with either of these?
     
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