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Connection/Identification problem — Parallax Forums

Connection/Identification problem

DonalbaneDonalbane Posts: 11
edited 2005-05-05 16:02 in BASIC Stamp
Hello, I'm trying to interface with a BS2p40, using the BS Editor v2.1.· I get Loopback and Echo, but no Device Type.· When I try to load code onto the stamp, I get the error box "No BASIC Stamp found."· The tutorial that I have suggests that the stamp has been found, but that it may not be powered.· I checked the power to Vdd and have +5V.· Is there anything else that I can check?

Thanks in advance.
Don

Comments

  • dandreaedandreae Posts: 1,375
    edited 2005-05-03 23:40
    Are you using a USB to Serial adapter?· If so, you may need to set the "Latency" to 1.· The Latency can be found in your device manager under the Port setting tab and then click on the advance button.· If this isn't the problem please contact tech support at 1-888-997-8267 with your set up ready to test.



    Dave

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    Dave Andreae

    Tech Support
    dandreae@parallax.com
    www.parallax.com

    ·
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-04 14:37
    I'm just using a straight serial connector.· Using a voltmeter:

    pin1 = -5.24V
    pin2 = -10V
    pin3 = 0
    pin4 = 0
    pin37 = 5V
    pin38 = 5V
    pin40 = 9mV

    The caps are in place, following the attached schematic.

    I spoke to technical support, but they said it sounded like a bad stamp.· I checked another board (essentially the same), and had the same problem.· I am more likely to believe that I'm doing something wrong rather than 2 stamps are both bad.· Has anyone else experienced a similar problem?

    Don
    connect.JPG
    491 x 205 - 16K
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-04 14:44
    Don,

    ·· Are these boards that you build yourself that you cannot get the Stamp to program on?· Do you have any Stamps that you have programmed on these boards before?· Or, have you successfully programmed any Stamps on this computer before?


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com


    Post Edited (Chris Savage (Parallax)) : 5/4/2005 2:48:45 PM GMT
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-04 14:49
    Yes. They are custom boards. Oh, I'm not sure if this is relevant but pins 8 and pins 33 are shorted together (with a 221 ohm resistor).

    Don
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-04 14:52
    I have not used these stamps before, nor this board before. However, I have programmed with the BS2 on other boards before.

    Don
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-04 15:04
    Donalbane said...
    I have not used these stamps before, nor this board before. However, I have programmed with the BS2 on other boards before.
    Don
    But have you programmed them on the machine you're having trouble with now?· We're trying to rule out the computer as a problem.· I am going to guess it's something with the boards though.· This wouldn't be uncommon with so many connections.· Do you happen to have a carrier board from us that you can test programming these Stamps on?

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-04 16:48
    Oh, sorry for misunderstanding. Yes, I have used this computer to program other stamp modules successfully. I do have a stamp tester board around somewhere, but not for the 40-pin variety. I checked out the I/O pins on the stamp, and they are all 0-40mV, except for 2 5V lines, so I don't think I'm sending anything in to mess with the stamp. Also, the stamp does not have any prior executable loaded onto it at this point.

    Don
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-04 17:44
    Don,

    ·· Given the information you have provided I would suspect the board.· It's highly unlikely that you have more than 1 brand new BS2P40 that are bad.· Perhaps you could re-construct just the programming parts (caps and DB9) wired to a breadboard with no other circuitry connected, and see if you can identify the Stamp.



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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-04 17:49
    OK, I can try that, but presuming that I get the stamp to work on a breadboard, I'm not sure how I would change the board to get the stamp to work. Since all the voltages on the pins are at expected values, how could the board possibly be affecting the stamp in such a way as to prevent it from functioning?

    Don
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-04 17:52
    Don,

    ·· Without seeing the board I wouldn't even venture to guess.· It could be a be something in the communications circuit.· It would be difficult to verify that without bypassing the capacitors in the circuit.



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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-04 18:28
    Do you have ExpressPCB? I could send you a copy of the board layout. The communications circuitry is just like the .jpg above, though.

    Don
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-04 21:24
    Don,

    ·· Yes, I do have ExpressPCB.· E-Mail me the layout and I will take a look at it tonight.



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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-05 14:38
    Don,

    ·· After looking at your PCB Layout, a fellow Tech and I have determined that your problem is you have shorted the /RES line to Vdd.· This is a bad thing since it prevents the Stamp from resetting, which is necessary for programming.· Normally the /RES line is internally pulled high (This is in the schematic), so you wouldn't need to do that anyway.

    ·· Assuming the Stamp Module wasn't damaged by this, you can try manually cutting the trace on the top layer of the board (your board)·carefully with an exacto knife.· This should work.· Let us know what happens.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-05-05 15:13
    A Dremel tool is also useful for PCB surgery ... ask me how I know!

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-05-05 15:28
    ·· Yes, a dremel tool would work, of course, as with the exacto knife you have to be careful.· One thing I noticed using a dremel to cut a line is that the bit tends to want to skate a little.· Basically you have to have a firm grip.· With the exacto knife, you tend to put extra pressure against the trace, and suddenly when it cuts, the knife shoots past the trace you're trying to cut and gets more than you want.· That I know!· It's not an exact science, you just have to be careful.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • DonalbaneDonalbane Posts: 11
    edited 2005-05-05 16:02
    Chris, that was the problem. Thanks so much for your help! Parallax tech support is the BEST! roll.gif

    Don
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