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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]

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
--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...
    show previous quotes

    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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