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USB Pic programmers

Discussion in 'Microcontrollers' started by Beefer3, Jun 12, 2005.

  1. Beefer3

    Beefer3 New Member

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    Hey everyone
    Has anyone had any experience with USB pic programmers? I am getting a really good deal on a new laptop and it does not come with a serial or parallel port. It does, howver come with 3 USB 2.0 compliant ports.

    If I was to use the laptop with my projects, I would have to obviously use the USB style programmers.

    So, does anyone have any good or bad stories they would like to share that would help me make my decision?

    Thanks
     
  2. upand_at_them

    upand_at_them Member

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    And then what do you do if you want to use the PIC's UART?

    Mike
     
  3. Jay.slovak

    Jay.slovak Active Member

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    Well using USB is OK... For example ICD2 from Microchip is using USB, and people say it's cool. USB provides enaugh power, so the programmer is free of additional power sources. :wink:
     
  4. dave

    Dave New Member

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  5. williB

    williB New Member

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    no experiencg with usb programmers , but as Jay said the usb port has plenty of power ..
    Myself , i designed and built my own pic programmer using the ports on the ISA bus..
     
  6. Jay.slovak

    Jay.slovak Active Member

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    Oh I remember that article, Nigel was pretty surprised somebody made such ISA programmer :lol:
     
  7. williB

    williB New Member

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  8. Beefer3

    Beefer3 New Member

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    Thanks guys.

    wiliB, that's an interesting programmer!

    If anyone has any experience with this programmer from Dontronics, I would love to hear you thoughts. The programmer is here http://www.dontronics.com/diyk150.html

    Thanks
     
  9. williB

    williB New Member

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    i wish i knew more about the usb protocol..
     
  10. evandude

    evandude New Member

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    I just bought one of those programmers ;-) it's been sitting on my desk for a few days, I don't have a 16V power supply to use it with, so I'm working on putting together a little capacitor charge pump circuit using a maxim chip so I can power the whole unit straight off the USB port.
     
  11. bryan1

    bryan1 Well-Known Member

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    Hiya beefer,
    While your checking out the usb programmer from dontronics take a look at the usb to serial adaptor. I bought 1 a few months ago as my laptop doesn't have a serial port and that adaptor works great. I first tried it out using a 16f877 to pc and it worked perfectly. There are a heap of similar devices around but in my opnion Don's is the best one available.
    By the way if your laptop has a parrallel port why not use that with a 16pro40 programmer?

    Hope this helps Bryan :D
     
  12. pittuck

    pittuck New Member

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    I've used a USB->Serial converter for my ICD2 (iddy bitty one) and it works. Got it off ebay for £5 + £1.50 P&P :D
     
  13. Jay.slovak

    Jay.slovak Active Member

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    What, the converter or ICD2 ?
     
  14. pittuck

    pittuck New Member

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  15. Jay.slovak

    Jay.slovak Active Member

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  16. Mike - K8LH

    Mike - K8LH Well-Known Member

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    Jay:

    How's your home-made ICD2 working for you? I just started fabricating one based on a design by Lothar Stolz...

    Regards, Mike
     
  17. Jay.slovak

    Jay.slovak Active Member

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    Yes, my ICD2 is based on Lothars design and it works great. Finally a perfect PIC programmer. I did some slight modifications to it, because I hated that Transistor tree and I also didn't like the OPamp solution due to step up converter used.
     
  18. Mike - K8LH

    Mike - K8LH Well-Known Member

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    Jay,

    May I ask what modifications you did to yours? I also am not happy with the transistor or the op amp solution... Mine is complete except for the Target MCLR circuitry and I also installed a 78M08 regulator for generating the 13v VPP voltage...

    Just hooked mine up to MPLAB for the first time a few minutes ago and successfully downloaded an OS and can read the ADC's in the Programmer>Status window... But it obviously faults with "no target device" and no voltages detected on the Target MCLR ADC resistors...

    Regards, Mike

    <added>

    Sorry, I should have mentioned mine is RS-232 not USB...
     
  19. Jay.slovak

    Jay.slovak Active Member

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    Ok, first I changed the power source, I used TL431 + 10K pot to set 13V, nice and stable. For the Transistor tree, first I tried to use 4051, which is analog multiplexter, but that didn't work because of 5V and 13V voltage levels. Then I decided to use two PC817, which are two opto-couplers, one is swithing output to GND, other one to +13V and to have an output at +5V I used schotky diode + 3K6 resistor to pull output High (+5V) when nether opto-couplers where turned on. And I also remade the RA0 sensing trimmer, added ERROR/BUSY/POWER leds and a PNP transistor which can be controlled by PC to ENABLE/DISABLE powering the programmed circuit from the ICD2. It took me a while to develop this version. I use 16F876 with original bootloader and it works Flawlessly!. 8)
     
  20. Mike - K8LH

    Mike - K8LH Well-Known Member

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    Thank you Jay... Your implementation sounds very nice... I'd love to see your schematic some time...

    May I impose again with a few more questions?

    <1> I'm aware of the active low "Busy" LED signal on RB3... Are there
    other LED signals available?

    <2> What pin on the ICD2 PIC provides the signal for a "Target VDD"
    high-side switch? Is it RA4? Is it also "active low"?

    <3> Is the target VDD always on effectively allowing only the "VDD First"
    method for placing a target PIC into high voltage program/verify mode?

    <4> I like your implementation of VDD on the MCLR pin using a diode
    and resistor... Do you happen to know, or, have you observed how the
    MCLR circuitry works? Can I assume MCLR is asserted low (reset) then
    taken to VPP when the ICD2 is ready to program a target? Can I also
    assume neither RC0 (VPP) or RC2 (Reset) are asserted during normal
    or debug operations?

    Regards, Mike
     
  21. Jay.slovak

    Jay.slovak Active Member

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    So...
    <1>Yes, there is also ERROR signal available at the RB2. Both ERROR and BUSY signals are Active HIGH, not low. And POWER signal si just led that is permanently on 8)

    <2>Yes RA4 (active low) is a signal for High Side switch, in my case BC327 PNP with 390R base resistor and some 4K7 pullup. I wanted to use MOSFET instead of PNP, but it was ten times more expensive, so I used PNP instead. PNP should suffice for low power applications, high power appliacations are self-powered anyways 8)

    <3>Ofcourse you can control when the target is powered from ICD (MPLABs setting), but I gues ICD2 can control this signal too to program PICs with internal oscilator and MCLR disabled. That's why I added that PNP to my ICD2, so that I can program 12F683 PICs without problems.
     

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