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need help with using 2 stamps at once — Parallax Forums

need help with using 2 stamps at once

betaboybetaboy Posts: 8
edited 2005-03-02 21:21 in Learn with BlocklyProp
how do u connect 2 BS2 stamps together, so they are being used in one program, but you increase the # of I/O
pins that are able to be used?

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-03-02 14:31
    User SEROUT on your "master" Stamp to send command messages to the "slave" (that uses SERIN to receive them).· Our help file shows how to user SEROUT/SERIN between Stamps with flow control so that messages don't get lost if the slave is busy doing the last task.· And this article from Nuts & Volts gives a specific master/slave example:

    http://www.parallax.com/dl/docs/cols/nv/vol3/col/nv81.pdf

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • Jim McCorisonJim McCorison Posts: 359
    edited 2005-03-02 16:27
    Betaboy,

    You can't directly connect a second stamp and have more IO pins. You have to write a program that runs in the second stamp and manages the IO lines and sends the data to the a program running on the first stamp.

    If you just want to have additional IO lines you'll want to use a decoder like a 74HC138 which will allow you to control 8 IO lines from 4 pins. You can cascade them to have even greater expansion, such as using only 5 pins to control 24 IO lines.

    Jim
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-03-02 21:21
    If you're looking at "dumb" expansion chips, consider the 74HC595 (outputs) and the 74HC165 (inputs). Very easy to use, stout, and we have lots of demo code for them.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
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