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demo board - # of usable I/O pins? — Parallax Forums

demo board - # of usable I/O pins?

ionymousionymous Posts: 29
edited 2008-10-21 13:31 in Propeller 1
I just ordered a propeller demo board.

The writeup says: "Eight unused I/O pins are available for experimentation"

The other 24 I/O pins must be used by the demo board for periperals: keyboard, mouse, TV out, VGA, etc.

If I am willing to go without some of these peripherals, can I regain the use of some I/O pins without much trouble?

Thanks for any help.
Ion

Comments

  • Paul BakerPaul Baker Posts: 6,351
    edited 2008-10-20 20:41
    No, there's no real easy way to reclaim the I/O pins from unused peripherals, it is possible with a lot of soldering experience to tack solder wires onto pins, but it isn't easy and leaves you with a pretty messy board.

    Some things can be tapped into, such as the HSYNC and VSYNC , and the PS/2 connectors, but they have series resistors, and in the case of the PS/2 pull up resistors as well, you don't get access to a bare I/O pin. Take a look at the schematic for the demo board to look for potential places to tap into.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • Jim FouchJim Fouch Posts: 395
    edited 2008-10-20 20:56
    All the I/O lines for the VGA adaptor have inline LEDs that could easily be used for status/debuging of your apps. This is not really reclaiming them, but it does allow you to use more then the 8 free I/O lines.

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    Jim Fouch

    FOUCH SOFTWARE
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2008-10-20 23:10
    Yes and No..

    Depending on what you are doing...

    I found a way to attach an Atari joystick (5 switches) to the VGA head a while back.

    Details here: obex.parallax.com/objects/87/

    OBC

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    New to the Propeller?

    Getting started with a Propeller Protoboard?
    Check out: Introduction to the Proboard & Propeller Cookbook 1.4
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  • ionymousionymous Posts: 29
    edited 2008-10-21 01:11
    It sounds like it isn't just easy to reclaim these I/O lines.

    I'll see what I can do with the 8 I/O pins for a while. Maybe by then I'll feel comfortable enough to get a prototype board where all 32 I/O pins are available.

    Thanks everyone,
    Ion
  • ionymousionymous Posts: 29
    edited 2008-10-21 12:53
    One more thing...

    I want my demo board to have serial communication to a PC, when my program is running. Just a simple TX/RX.

    The demo board has a serial connection for programming it.
    Once my code is loaded, can it use this serial connection?

    If so, I won't need to use 2 of my 8 available I/O pins for this serial connection.

    Ion
  • parts-man73parts-man73 Posts: 830
    edited 2008-10-21 13:26
    Yes, after programming, P30+P31 can be used as TX+RX respectively right to the USB port of your computer.

    See www.parallax.com/tabid/442/Default.aspx and download the Parallax Serial Terminal. It's not the only way to talk serially to your Propeller, but it's a good choice.

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    Brian

    uController.com - home of SpinStudio - the modular Development system for the Propeller

    PropNIC - Add ethernet ability to your Propeller! PropJoy - Plug in a joystick and play some games!

    SD card Adapter - mass storage for the masses Audio/Video adapter add composite video and sound to your Proto Board
  • ionymousionymous Posts: 29
    edited 2008-10-21 13:31
    Great! Thanks Brian
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