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Smart Mode in Parallax GPS — Parallax Forums

Smart Mode in Parallax GPS

MayankMayank Posts: 6
edited 2009-05-18 14:48 in General Discussion
Hi everyone,

I have purchased the Parallax GPS Receiver Module for my project, but I have a problem pertaining to the "Smart Mode".
In "Smart Mode" since the company has provided only one pin for serial I/O, I am not sure how to connect the single pin with the RX and TX pins of the MAX232. In "Raw Mode" this is not the problem, as only Tx inis required there, but what about "Smart Mode"!!

If possible can anybody send me the schematic diagram of connection in the "Smart Mode"?

Waiting for an early response!!!! shakehead.gif

Comments

  • MayankMayank Posts: 6
    edited 2009-05-17 05:38
    Please let me know it as early as possible..
    Its really very urgent..
  • FranklinFranklin Posts: 4,747
    edited 2009-05-17 20:22
    http://forums.parallax.com/showthread.php?p=640507

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    - Stephen
  • MayankMayank Posts: 6
    edited 2009-05-18 01:34
    I have seen that forum.
    But again They have mentioned about Raw Mode, I am asking about Smart Mode.
  • steve_bsteve_b Posts: 1,563
    edited 2009-05-18 12:05
    www.parallax.com/Portals/0/Downloads/docs/prod/acc/GPSManualV1.1.pdf

    Do you need to use a MAX232?
    You don't say with uprocessor you're using, but certainly the BS2 allows you to use inverted and true rs232/ttl signals.

    If you must use the MAX232, then it's really nothing different.....you're just connecting a signal converter (changing ttl to rs232).

    You'll probably want to use a 120ohm resistor between the GPS SIO and the MAX232's tx and rx lines (yes, tie them together).
    Then connect the stamp/sx/prop to the max232 as if there were two separate pins.
    Now it's just a matter of timing.
    Serout <command>
    wait <some small amount>
    Serin <response to my command>

    The GPS manual (link at top) has the smart mode example....they show:
    SEROUT Sio, Baud, [noparse][[/noparse]"!GPS", GetInfo]
    SERIN Sio, Baud, 3000, No_Response, [noparse][[/noparse]ver_hw, ver_fw]

    So, in the example, they don't use the "wait" command, but do use a timeout. So they switch from serout directly to serin and just wait til something comes down the line.

    If you are hard pressed for i/o's on your board, and don't want to waste 2 pins on tx/rx....then you'll just have to manage your timing with the same serin/serout pin.

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    <FONT>Steve



    What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
    Lee Travino after the second time being hit by lightning!
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-05-18 14:48
    The circuits listed are for the electrical connections. The RS-232 to PSC should work fine since it's the same type of interface.

    Your duplicate post in the Sensors Forum has been removed.

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    Chris Savage
    Parallax Engineering


    Post Edited (Chris Savage (Parallax)) : 5/18/2009 3:33:25 PM GMT
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