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programming without the board — Parallax Forums

programming without the board

jeanjean Posts: 21
edited 2006-03-28 22:50 in BASIC Stamp
I was wondering if I could reprogram my bs2-pe without connecting it to the proramming board, say with a serial cable?
Is it 4 pins? Sin, Sout, Vss, ATN?
thank you

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-03-28 15:39
    jean,

    ·· Yes, those are the required connections and the diagram is attached.· You'll notice there are two capacitors which may or may not be needed in your application, but should probably be included anyway just in case you ever need to use a computer that does require them.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
    Serial Port Connections.JPG
    682 x 394 - 31K
  • jeanjean Posts: 21
    edited 2006-03-28 15:59
    thank you, and for stam daq do we need to connect the ground besides Sin, Sout
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-03-28 17:08
    jean,

    ·· You always want a common ground when communicating between two devices.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Jeff DegeJeff Dege Posts: 85
    edited 2006-03-28 17:33
    I know that with many serial ports, the capacitors aren't necessary, but there are some that won't work without them.

    Are there any that won't work with them?

    And are there limitations on where they should be placed? Should they be placed on the circuit board near the Stamp? Or could they be wired inside the DB-9 connector shell? Or does it not matter at all?
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-03-28 17:53
    It will always work with them -- so put them into your circuit (as we do on our boards). If you don't, you risk having the external device/program maniuplate the DTR line in such a way that puts/keeps the Stamp in reset when you don't want that.

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    Jon Williams
    Applications Engineer, Parallax
  • Jeff DegeJeff Dege Posts: 85
    edited 2006-03-28 19:16
    If I'm including a DB-9 connector on the board, so that I can program the Stamp with any standard serial cable, I'll put the caps on the board.

    But I prefer four-pin headers, which require a custom cable, but take less space on the board. Would the caps work as required if they were soldered into the DB-9 shield at the PC end of the custom cable, instead of on the board?
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-03-28 19:58
    I think it would be better to put them onto the board. Note that if you don't follow the loopback part of the schematic you will not be able to "auto find" the BASIC Stamp.

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    Jon Williams
    Applications Engineer, Parallax
  • Jeff DegeJeff Dege Posts: 85
    edited 2006-03-28 21:11
    I've been wiring DSR to RTS inside the DB9 connector shield. Why you'd run six wires to the Stamp when only four of them connect to anything on the board I don't know. Particularly when everybody and his brother has piles of four-conductor cable lying around in the backs of their desk drawers and six-conductor cable has to be bought special.

    I've been putting a four-pin header immediately adjacent to pins 1-4 of the Stamps' sockets, and wiring them straight. With the serial ports I've been using, it's never been a problem. If I add the caps on the board, I need to connect one in serial between the header and the stamp, which wrecks the tight, simple configuration that I've been using.

    I don't I've yet put a Stamp circuit on PC board that was laid out so that the caps could have been placed without significant reorganization.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-03-28 21:53
    Do what you think is best. You'll find, though, that if you lose that special cable and have to jury-rig another you may wish that the caps were onboard instead of in a now-missing cable.

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    Jon Williams
    Applications Engineer, Parallax
  • Jeff DegeJeff Dege Posts: 85
    edited 2006-03-28 22:02
    My only concern is whether there's any electronic reason why the caps should be on one end or the other. By my understanding of what's going on, it shouldn't matter. But there are some uses of caps where position very much does matter, and I was wondering whether this was one of them.

    I could have tested it myself - except, of course, I don't have a computer with a serial port that shows the problem.

    As for custom cables, if I'm using a custom connector on the board, I'm going to need a custom cable no matter what I do.

    But if I ever put a standard DB-9 on a board as a programming port to the Stamp, you can be sure I'll put the caps on the board.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-03-28 22:03
    You'll have to try it; I don't think there will be a problem -- but I don't know with certainty without testing.

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    Jon Williams
    Applications Engineer, Parallax
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-03-28 22:50
    Jeff,

    ·· The main thing the caps do is prevent the DTR line from being held HIGH by computers that do that when the port is closed.· I would recommend putting the caps right on your BASIC Stamp Board, although I don't think it matters it they're in the cable.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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