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Why does Hydra use 10 MHz crystal? — Parallax Forums

Why does Hydra use 10 MHz crystal?

RaymanRayman Posts: 14,791
edited 2007-10-10 00:13 in Propeller 1
Anybody know why the Hydra uses a 10 MHz crystal and the proto and demo boards use 5 MHz?· Just seems to add unnecessary confusion since both wind up working at 80 MHz anyway.· Or, am I missing something?

Comments

  • Ken PetersonKen Peterson Posts: 806
    edited 2007-10-09 12:20
    Perhaps purchasing got involved smile.gif

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    The more I know, the more I know I don't know.· Is this what they call Wisdom?
  • Paul BakerPaul Baker Posts: 6,351
    edited 2007-10-09 16:57
    The Hydra was developed by a 3rd party (Andre'), and he made his own design decisions when creating the hydra.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • deSilvadeSilva Posts: 2,967
    edited 2007-10-09 17:20
    The crystal is on a socket and can easily be exchanged by any other value.
    I have the suspicion that Andr
  • Mike GreenMike Green Posts: 23,101
    edited 2007-10-09 17:28
    Regarding the keyboard and mouse circuitry ...

    There is already a keyboard driver (obex.parallax.com/objects/105/) that is configurable at runtime to use either the Hydra convention or that used by the other Propeller boards. The same thing has not been done yet for the mouse driver, but it's doable. In any event there are two different versions of the mouse driver that are "drop-in" replacements for each other.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2007-10-09 17:45
    deSilva, you are very close to the truth, originally there was hope of being able to operate @ 160 (before anything was commited to silicon), but for a slew of reasons it was determined that was an unrealistic goal and would result in low yield. There is a similar story with the PS/2 logic, the hydra's isolated version is an older circuit used on the original (beta only) demo board. Because the Hydra is as much a software product as a hardware product, the hardware needed to be codified so that the game developers had a stable platform to write thier games on. Meanwhile because the demo board is mostly a hardware product, it was free to continue to evolve right up until the product release date.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • Fred HawkinsFred Hawkins Posts: 997
    edited 2007-10-10 00:06
    (seems the right place to ask)

    Paul, when was that product release date?
  • Paul BakerPaul Baker Posts: 6,351
    edited 2007-10-10 00:13
    I believe it was April of 06, the Hydra was availible for the Christmas season of 06 (so Novemberish).

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
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