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Javelin board expensive — Parallax Forums

Javelin board expensive

Robot FreakRobot Freak Posts: 168
edited 2006-11-18 21:13 in General Discussion
hello,

I want to buy a robot kit with Java , so I came out to javelin...
Then I looked at the prices and saw that the Javelin Breadboard is very expensive...
I think it's very expensive because the basic stamp 2 breadboard is a lot cheaper...
Why is this ? Only for the extra COM port ??

thank you

Peter van Lith
·

Comments

  • Ken GraceyKen Gracey Posts: 7,403
    edited 2006-10-16 19:33
    Peter,

    Lower volume, higher cost. That's the only reason.

    Ken Gracey
    Parallax, Inc.
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2006-10-16 19:49
    You can use the javelin on any of the basic stamp breadboards
    that supports the DIP24 footprint. You do not really need
    the 2nd com port, but it is handy.
    http://www.parallax.com/html_pages/products/boards/programming_boards.asp

    regards peter
  • Robot FreakRobot Freak Posts: 168
    edited 2006-10-16 19:54
    Ken Gracey (Parallax) said...
    Peter,

    Lower volume, higher cost. That's the only reason.

    Ken Gracey
    Parallax, Inc.
    do you mean that they don't make many javelin breadboards

    Post Edited (Peter van Lith) : 10/16/2006 7:58:00 PM GMT
  • Robot FreakRobot Freak Posts: 168
    edited 2006-10-16 19:56
    Peter Verkaik said...
    You can use the javelin on any of the basic stamp breadboards
    that supports the DIP24 footprint. You do not really need
    the 2nd com port, but it is handy.
    http://www.parallax.com/html_pages/products/boards/programming_boards.asp

    regards peter
    i know that but thank you
  • Kevin WoodKevin Wood Posts: 1,266
    edited 2006-10-16 22:24
    The more Javelin development boards Parallax sells, the bigger the discount they can get when purchasing the raw parts in volume, since they will buy more raw parts. This will result in lower prices.

    They could build more boards, but if their sales volume doesn't increase, there would still be no savings. In fact, the prices would need to go up, due to the increase in production costs, labor, inventory, etc.
  • Robot FreakRobot Freak Posts: 168
    edited 2006-10-17 06:23
    so javelin is not very popular
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-10-17 14:59
    Peter,
    ·
    ·· Remember, the Javelin can be used on any of our Development Boards which support a 24-pin Stamp Module.· This does not reflect the popularity of the Javelin module itself.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
  • GJGJ Posts: 19
    edited 2006-11-18 18:24
    The javelon has the advantage of running VPs, this is a benefit I think other devices don't have. Also, the java programming provides some benefits and java is a strongly supported language.

    That said, I would like two see two things incorporated,
    1) More speed
    2) Less cost

    Thus far, I've been able to accomplish what I've needed to. One does need to think about their program and make sure it is effecient. Likewise, the serial communications, which has nothing to do with the javelin, is slow.

    Does anyone know if shiftout would work better than a uart and if one could use shiftout and go straight to usb or ethernet?
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2006-11-18 18:59
    The serial communications is not slow, the javelin can reliable send at 57600 and reliable
    receive at 28800. The bottleneck in the throughput speed is due to the java virtual machine
    that interprets java byte codes. This throughput limit also applies to shiftin and shiftout.
    The throughput limit is about 1000 bytes/second.

    The javelin runs at 25MHz clockspeed. The sx48 on the javelin module can run at 75MHz
    but that triples the power consumption which exceeds the onboard switched regulator
    specifications.

    I have modified the original Uart class to use a public char array rather than a private int array.
    http://tech.groups.yahoo.com/group/JavelinCode/files/Javelin%20Stamp%20IDE/lib/stamp/core/
    If you want to use this modified class, rename the original Uart.java to Uart.java.org and
    download the modified Uart.java
    Because I used a public array, this modified class allows you to access it directly
    which may help to increase throughput, because a ram-to-ram copy can be skipped.

    regards peter
  • GJGJ Posts: 19
    edited 2006-11-18 20:25
    Thank you.
    My main point in the serial communications wasn't actually referring to the javelin, more so to the serial comms itself. Even at 57.6, it does take time to any amount of data.

    You bring up something very interesting though. Can one overclock the SX48? Would it be as simple as providing power and replacing the resonator? Or would one have to change the actual interpreter?
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2006-11-18 21:13
    I think you can replace the oscillator (the javelin uses no resonator)
    and power the javelin via its 5V pin (leaving Vin disconnected).
    If you double the oscillator freq to 50MHz, then the javelin
    clock tick becomes 4.34usec and all baudrates and other timings become doubled.
    (eg. 28800 becomes 57600).
    You won't be able to program the javelin because the
    programming baudrate would also double, although it might
    be possible to change that in the javelindirect source.
    Another possible programming problem is writing to the onboard eeprom
    because the required write delays are shortened
    and may become too short.
    Obviously, any attempt to do such an operation will
    void the warranty of the javelin module.

    regards peter

    Post Edited (Peter Verkaik) : 11/18/2006 9:17:34 PM GMT
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