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Javelin Speed Concern — Parallax Forums

Javelin Speed Concern

hacktorioushacktorious Posts: 72
edited 2007-02-22 16:16 in General Discussion
I have been looking around at other stamps and noticed the Javelin seems to be very slow (8000 ins/sec). How concerned should I be about this? Also, I noticed on the Parallax Javelin page it mentions the 8000 figure doesn't include background tasks; does this make the Javelin more comparable to faster microcontrollers? Thanks.

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Scott

Comments

  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2007-02-22 15:57
    The 8000 reflects the speed of the main level code. The background tasks (Virtual Peripherals)
    operate independant of the main level code. A uart for example, will continue to receive or send
    from a 256byte buffer, while executing your mainlevel code.
    Of course, having running more VP's simultaneously, does have a small effect on the
    speed of the mainlevel code. You can run 6 VP's simultaneously, but you can define more.
    In that case you need to stop a VP and start another.
    To give another impression, you can transfer approx. 1000bytes/second from
    array to array with 3 uarts running.

    regards peter
  • Mike GreenMike Green Posts: 23,101
    edited 2007-02-22 16:16
    Keep in mind that the underlying microprocessor is essentially the same for the Javelin and the newer (BS2p) Stamps. There is a major difference in that the interpretive code is fetched from a serial EEPROM (relatively slowly) with the BS2p and from a parallel RAM (fast) with the Javelin. The Javelin makes use of the SX processor's rapid interrupt processing to do some I/O (the virtual processors) in parallel with the Java interpreter.
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