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native USB with Prop II? — Parallax Forums

native USB with Prop II?

RaymanRayman Posts: 14,162
edited 2008-04-01 21:13 in Propeller 1
Any chance the upcoming Prop II will have native USB connectivity?· Maybe with a couple external xistors to handle the 5V?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-04-01 14:45
    I doubt it. The philosophy of the Propeller is that it has very little dedicated hardware, that everything is done in software. The video hardware has been the only exception because it's really just a fancied up shift register that has other uses as well and most of the video generation work is still done in software. The counters are pretty general purpose devices as well.

    Given that native USB support requires a lot of special purpose hardware and that there are some nice chips on the market that take over most of the signal processing burden (like the MAX3421E), it makes little sense to dedicate chip area for something that would only be used part of the time.
  • RaymanRayman Posts: 14,162
    edited 2008-04-01 14:56
    To me, the benefit of the Prop is that I can do a lot without external chips. USB is the one thing lacking... (Although somebody did get the Prop to appear as a keyboard and send keystrokes with Windows).

    I've noticed that somehow other microcontrollers have inherent USB connectivity. But, I imagine they just licensed somebody's design and included it on the silicon... But, couldn't Parallax do this too? Or, maybe a USB UART could be done with software?
  • hippyhippy Posts: 1,981
    edited 2008-04-01 16:26
    The USB UART in software works (CDC), but requires two cogs.

    There's no reason I can see that this couldn't be used to allow program download with the right PC boot loader software. It would require the Propeller to also be running the right code and I'm not sure how you'd force a 'reset' via USB this way to enter boot loading mode.

    That USB interface is just three R's and a socket.
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2008-04-01 16:40
    This is pretty high on my wish list as well..

    There's a lot of hardware that we could attach to the prop with a USB interface.

    Perhaps the compromise of a VNC1L-1A interface for breadboard users would
    be a good solution? Off the top of my head, perhaps a VNC1L/Propeller combination
    much like the PROPGFX idea? I've been putting off playing with SSOP, largely
    due to intimidation, but perhaps it's time.

    OBC

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  • Ken PetersonKen Peterson Posts: 806
    edited 2008-04-01 21:13
    What is it about USB that can't be done in software (on the PII)? It should have way more capability than the current Prop. If there's room in ROM, perhaps it can be implemented on boot.

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