PIC in circuit programming

Discussion in 'Embedded Systems and Microcontrollers' started by dayv3, Jun 5, 2015.

  1. dayv3

    Thread Starter Member

    May 22, 2014
    Hi All,

    I just finished my next project but I want to program the 12f683 in circuit instead of
    pulling the chip and putting it in my zero insertion force socket like I have in the past.
    But I have a question.

    Luckily, I was able to reserve the clock, data and not MCLR pins exclusively for chip programming.
    Maybe I missed it in the data sheet but when the chip is programmed is the power only coming from my
    PicKit2 on a dead circuit board? or do I need to have power connected to the circuit in addition to the
    power coming from the PicKit2?

    Is there anything else that I need to be aware of?

  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    The power comes from... well... it depends.

    The simplest thing to do is to allow the PICkit to power the device so the loader program (on your PC) is in full control of the process. This has the limit of how much current the PICkit can supply. So while it is my favorite way to program a part for larger projects it can’t be done.

    When you need more current then just turn your whole device on. The PICkit will sense that voltage and actually use it so it matches your Vdd with it’s drive signals.

    Isolating MCLR PGDAT and PGCLK is IMHO the best way to go as it not only insures a trouble free programming cycle but also allows in circuit debugging of your project. I trust you know the PICkits are capable of doing that.
  3. MaxHeadRoom


    Jul 18, 2013
    I generally use either my Pickdemo board for test programming or the final board itself, in both cases I use an external board supply to overcome possible low current.