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Inchworm project started

Discussion in 'Microcontrollers' started by williB, Feb 23, 2007.

  1. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Found it

    Read this thread. The person there was going through the same process, it starts with parts questions and follows the same path you are traveling. It contains some good info.
     
  2. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Are you using a PC with a true serial port or a USB to RS232 adapter?

    You may have a port conflict, make sure you don't have two devices assinged to a single com port. From the hardware manager you can configure the port # and turn the FIFO buffers off.
    Don't forget the Inchworm requires a DC power adapter. At least 100ma @ 9 to 15 VDC tip positive.
    Device Manager will let you see and change the settings.
    • Select 16F877 from the config menu before selecting the programmer
    • select programmer / icd2
    • select programmer / settings / communications (COM1 or 2 only)
    • select programmer / download OS (it will come up with a file, select it)
    • wait, you should get an busy led flickering
    Should now work.

    Device Manager should look similar to this.
    [​IMG]

    Advanced Settings Tab
    [​IMG]
     
    Last edited: Feb 24, 2007
  3. williB

    williB New Member

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    Sorry to be such a pain in the arse.
    it is a true serial port
    thank you again 3v0, im reading the rest of that now..
    will get back to yall..
    i have to test the cable , with sv0's suggestions
    i have to test the board , with a scope
    i will report the findings in a little bit.

    EDIT it has no internal modem
     
    Last edited: Feb 24, 2007
  4. dave

    Dave New Member

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  5. williB

    williB New Member

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    pins 13 & 14 show no oscillator action with the scope
    i've attached a photo of the board
     

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  6. williB

    williB New Member

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    between pin 12 and pin 11 shows 5.08V

    EDIT::i have to go out for a little bit , back soon
     
    Last edited: Feb 24, 2007
  7. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    I am thinking you know and did all this but check again.

    All the PIC16F877(A) needs to work is
    • the 4 power/gnd, (bypass caps on each pair)
    • a 20MHZ clock source (and caps if crystal)
    • a 10K resistor on pin 1 to pull the (active low) reset high.

    pins 12 and 31 are ground
    pins 11 and 32 are +5
    IIRC the green led works so you can not have them backwards.

    If that is all right and if you have the right caps for the osc then you should see the osc osc on the scope. (pins 13,14)

    You checked for solder bridges? Esp near the crystal and its caps.

    Now check both pins 13 & 14 with the scope.

    At this point I would pull the processor and see if I could make it work on a solderless breadboard. But that is me and I do not know if you have a ceramic resonator or crystal with caps.

    If it is still flatline you either have a bad chip or it is not programmed.
     
  8. blueroomelectronics

    blueroomelectronics Well-Known Member

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    It's rare but I've seen a dead crystal once.
     
  9. williB

    williB New Member

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    good idea i was thinking the same thing
    i'll take the 877 out and breadboard it , i have a ceramic resonator.
     
  10. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Did you use a x10 probe?, a x1 probe will usually stop the oscillator anyway!.
     
  11. williB

    williB New Member

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    i had some space on the breadboard.
    should it work with a resonator on pin 13 ? if it was programmed to use the crystal?
    i dont remember

    what i usually do is measure pin 14 on the scope ,with a resonator connected to pin 13, to see if it is running..
     
  12. williB

    williB New Member

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    i didnt use a x10 probe , dont have one .
     

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  13. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    In that case not detecting oscillation isn't very conclusive, you could make a crude x10 probe (as you're not requiring accurate compensation) by simply adding a 9Meg resistor to the end of the probe.

    Crystal failure (or the uP not oscillating for some other reason) is a common fault in lots of electronic equipment, one of the first tests is to scope the oscillator pins - but it is essential to use a x10 high impedance probe.
     
  14. williB

    williB New Member

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    should it work with the resonator ,if it was programmed to use the crystal?
     
  15. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Yes, ceramic resonators use the same setting - and they even have the capacitors built-in.
     
  16. williB

    williB New Member

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    if thats the case , its flatlined
     
  17. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Assuming that breadboard layout is what you're measuring?, I find it difficult to even spot a resonator? - and certainly the long wires everywhere, and complete lack of supply decouplers, isn't going to help.
     
  18. williB

    williB New Member

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    thats the resonator right above the pic
     
  19. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Yes you should add the caps.
    You also need the 10K pullup on pin 1.

    Do not get discouraged, this is good experiance for what you will be doing when you get the programmer working.

    The only probe I have is a 10x. I missed that one.

    Not sure about how you have the resonator hooked up.
     
    Last edited: Feb 24, 2007
  20. williB

    williB New Member

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    EDIT
    you are right , i need the power to MCLR also
     
  21. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    What, you mean the silver box?. That looks like an oscillator module, not a resonator.
     

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