pickit2 clone question

Discussion in 'Embedded Systems and Microcontrollers' started by blind2_man, Feb 13, 2013.

  1. blind2_man

    Thread Starter Active Member

    May 12, 2008
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    I have a homemade clone of pickit2 with schematic
    Junebug%2520Assembly%2520Instructions-5.jpg
    Can this clone program 3V3 pics (eg. dspic33fj64gp804)?
     
  2. t06afre

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    May 11, 2009
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    If you look at the datasheet you will see that the PGEC2 and PGED2 are 5 volt tolerant pins. And hence can be connected to the junebug device that is a 5 volt device. The "dspic33f family reference manual" state that
    And hence for debugging​

    .​
     
    Last edited: Feb 13, 2013
  3. Markd77

    Senior Member

    Sep 7, 2009
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    I haven't looked at the datasheet or programming specification, so I don't know if everything else is right, but make sure that you provide 3.3V power to the PIC and find the option in your programming software for external power (not powered by PICKIT 2).
     
  4. t06afre

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    Come to think about it. Your PIC use low voltage programming. But still the MCLR pin on the PIC is important during the programming cycle. I am not sure if the junebug only support high voltage programming. This is normally taken care by the software in the background and by setting the proper configuration bit. So I have not given it much thinking. Any idea around this Mark? By the way. The MCLR pin is also 5 volt tolerant on the PIC the OP use
     
  5. ErnieM

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    Apr 24, 2011
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    One quick way to check this is to use MPLAB: hit up the menu for Configure | Select Device... and enter the PIC you are considering using. You get instant indication of what programmers and debuggers work with that part.

    Otherwise, this programmer will NOT work without modification. It only provides 5V for Vdd (U5V), and you need to drop this down for that part.

    Did you build this yourself? Does it work? What programmer did you use to program the PIC18F2550 inside this programmer?
     
  6. t06afre

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    I sent a PM to Blueroomelectronics, and asked for some help. Bill is the best man to answer this
     
  7. Markd77

    Senior Member

    Sep 7, 2009
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    I just lost my longer reply, but basically I checked the schematics and the Junebug can control VPP and VDD the same as the PICKIT 2.
    Clock and Dat pins are level shifted on the PICKIT 2 but not the Junebug.
    Maybe a pair of 3.3V zeners would be a good safety precaution.
    AUX pin is missing on the Junebug but not required for this PIC.
    PICKIT2 schematic is at bottom of this datasheet:
    <ed> Link didn't work. Look for PICKIT2 Microcontroller programmer users guide link near the bottom of this page:
    http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en023805
    </ed>
     
    Last edited: Feb 13, 2013
  8. blind2_man

    Thread Starter Active Member

    May 12, 2008
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    If I insert a 3v3 LDO in debuger to run all stuff on 3v3, is it posible this?

    I use PGED2/PGEC2 to connect the debuger.

    I have builded myself used to program/debug 16f876A/16f84A/18f4550 and dspic30f2020.

    If I measure on VDD out of debuger I never seen other then 5V or 0V on VDD.
     
  9. Markd77

    Senior Member

    Sep 7, 2009
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    Maybe just give it a try with no PIC attached with settings for the 33F PIC and measure VDD and VPP.
    It might detect there is no PIC connected too quickly to get a measurement, but worth a try.
     
  10. t06afre

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    As long as the MCLR, and PGED2/PGEC2 pins are 5 volt tolerant pins. I would not mess with inserting a 3.3 volt LDO to power the MCU used in the junebug. That will for sure create other problems. What you instead could do is to use a 3.3 volt LDO on the USB 5 volt rail. And use this to power the PIC during programming experimenting. But if you already have 3.3 volt source on your board. You can use this. You do not have to connect the junebug VDD if you already have a suited power source. As long as the junebug/development board has a common GND during programming and debugging
     
  11. blind2_man

    Thread Starter Active Member

    May 12, 2008
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    I have done this andI have following error:
    Initializing PICkit 2 version 0.0.3.63
    Found PICkit 2 - Operating System Version 2.32.0
    Target power not detected - Powering from PICkit 2 ( 3.25V)
    PK2Error0024: PICkit 2 was unable to establish a valid Vdd on the target (Attempted 3.25V - Read 4.99V)
    PICkit 2 Ready


    The question still remains my clone has a problem or the schematic is not made to power 3V3 pics.
     
  12. t06afre

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    Yes that is correct. In your schematic the power to the ICSP port. Comes dirrectly from the USB 5 volt power rail. And hence it can not power any 3.3 volr device without inserting a LDO. But doing so. You should be able to power at least your dspic33fj64gp804 as it has some 5 volt tolerant pins
     
  13. Markd77

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    Sep 7, 2009
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    I just noticed that the part of the circuit for adjusting VDD is only connected to the ICD connector, the pins are in a different order to the ICSP connector, but otherwise should function the same.
     
  14. blind2_man

    Thread Starter Active Member

    May 12, 2008
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    Could be a solution not to connect VDD at all and use only development board power supply the dspic, I will try.
    One more question, is it possible by mounting one of transistors BS250 /2n7000 wrong can have this behavior: 0/5V on VDD output?
     
  15. t06afre

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    Did you mean VPP and not VDD:)
     
  16. blind2_man

    Thread Starter Active Member

    May 12, 2008
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    I mean VDD pin 3,4. If I understand correctly the transistors Q2 = BS250 and 2N7000 controls the pin3 in connector VDD target via diode 1n5817 that it is a sckoty diode opening on 0.2V. Am I understanding in the wrong way? What 3v3 programing means? Supplying 3v3 on the 3 pin and apply some programing voltage on VPP and sending data via PGM/PGD.
     
  17. blind2_man

    Thread Starter Active Member

    May 12, 2008
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    Did you have debug a 3v3 pic with junebug ?
     
  18. Markd77

    Senior Member

    Sep 7, 2009
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    After another look the junebug is actually missing some of the parts for controlling the voltage of VDD, so you get only 5V on the ICSP connector and about 4.8V on the ICD connector which can be switched on or off using Q2 and Q5.
     
  19. blind2_man

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    May 12, 2008
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    Thank you.
     
  20. t06afre

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    The junebug uses the PICKIT 2 firmware. According to the PICKIT 2 supported devices. No debug header will be needed. So you should be able to both program and debug your DSPIC chip. But it may be you have to upgrade the firmware
     
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