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What if Propeller drives P31 ... — Parallax Forums

What if Propeller drives P31 ...

jazzedjazzed Posts: 11,803
edited 2009-04-22 17:38 in Propeller 1
What if Propeller drives P31 ... the same time as PropPlug over time ?

I assume a 1K resistor between P31 and the PropPlug would prevent damage.
Could I use a smaller value? Am I just being paranoid?
What's the right thing to do? I really need that extra pin [noparse]:)[/noparse]

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--Steve


Propalyzer: Propeller PC Logic Analyzer
http://forums.parallax.com/showthread.php?p=788230

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-04-21 06:59
    You could use an even bigger resistor between P31 and the PP's TX pin, if you like. Whatever else you need to connect to P31 can be connected directly.

    -Phil
  • AleAle Posts: 2,363
    edited 2009-04-21 10:11
    I made myself a proplug and included a resistor in every line, just for these cases.
  • KPRKPR Posts: 189
    edited 2009-04-21 13:21
    Ale said...
    I made myself a proplug and included a resistor in every line, just for these cases.

    Got any pics and your schematic??

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    New ICON coming, gotta wait for the INK to heal, now we have colour!
  • AleAle Posts: 2,363
    edited 2009-04-21 13:39
    Pics ? No, schematic ? just add a series resistor (I used 453 ohm, have loads of them) in the TXD and RXD lines. Standard FT232.
  • jazzedjazzed Posts: 11,803
    edited 2009-04-21 14:52
    Thanks Guys.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    --Steve


    Propalyzer: Propeller PC Logic Analyzer
    http://forums.parallax.com/showthread.php?p=788230
  • KPRKPR Posts: 189
    edited 2009-04-22 16:33
    Ale said...
    Pics ? No, schematic ? just add a series resistor (I used 453 ohm, have loads of them) in the TXD and RXD lines. Standard FT232.

    Sorry.. like this?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    New ICON coming, gotta wait for the INK to heal, now we have colour!
    diag.GIF
    651 x 740 - 5K
  • SapiehaSapieha Posts: 2,964
    edited 2009-04-22 17:14
    KPR said...
    Ale said...
    Pics ? No, schematic ? just add a series resistor (I used 453 ohm, have loads of them) in the TXD and RXD lines. Standard FT232.

    Sorry.. like this?

    Hi KPR.

    Like this! Yours is not in series with PropPlug

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
    diag2.GIF
    335 x 402 - 4K
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-04-22 17:21
    Well, I wouldn't do it that way either. I'd put the resistors between the Prop Plug and the In/Out lines. Also, you need to make sure that the other device connected to P31/P30 does not output to those lines, since it will not be tri-stated upon reset like the Propeller's pins and will conflict with any communication that's taking place. If this is a problem, you may need to dedicate a third pin with a pullup (or a switch) to key an analog multiplexer between the Prop Plug and the other device.

    -Phil
  • SapiehaSapieha Posts: 2,964
    edited 2009-04-22 17:38
    Hi Phil.

    I know.
    But it was only question on SERIES with Propeler.
    It is not good For use PropPlug in Parallel with any other device.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
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