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Re: I/O device, Collaborative project

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  • andyolney
    I have been watching the progress of this USB box at the yahoo group geckodrive designed for the machine tool crowd. The current specification, while
    Message 1 of 55 , Dec 4, 2004
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      I have been watching the progress of this USB box at the yahoo
      group "geckodrive" designed for the machine tool crowd. The current
      specification, while designed for a machine tool, might be useful in
      the robotics world. This is the current list of functions. The
      software interface will be/is published and I think he is using a
      rabbit and a fpga to run it. Mariss has not stated a price but he is
      a manufacture of stepper and servo drives and seems to have
      reasonable prices. I am guessing!! $200-$250.

      At least it is an example of what can be done.
      Andy Olney

      Hi,

      The G204V "Vampire" drive design is finished. The first 100 beta
      units will be available at the beginning of January.

      That means I'm back on the G2002 (G2005?) project. The FPGA for the
      design is being coded right now. In summary, the G2002 will have:

      1) 6 axis of step / direction (up to 4 MHz step rate)
      2) 6 axies of encoder feedback (CH-A, CH-B, Index and Fault)
      3) 8 analog output channels (+/-10V, 0-5V)
      4) 8 analog input channels (0-5V)
      5) 16 general purpose outputs (5-24VDC, 100mA)
      6) 16 general purpose inputs (+/- 100V protected)
      7) USB interface, USB powered

      Mariss
    • Jeffrey Birt
      Thanks for clarifying this Paul. On Tue, 18 Jan 2005 10:05:33 -0800 (PST), Paul Jurczak ... -- Jeff Birt Electronics Engineer Integrated Systems Facility
      Message 55 of 55 , Jan 18, 2005
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        Thanks for clarifying this Paul.


        On Tue, 18 Jan 2005 10:05:33 -0800 (PST), Paul Jurczak
        <pauljurczak@...> wrote:
        >
        > Jeff,
        >
        > the issue to consider here is that the data on USB1.0 bus is formatted into
        > frames, which are 1ms long (1kHz). That presents latency issues. Lets say that
        > you want to send a request to your microcontroller and get a response back. It
        > will take not less than 4 frame periods (4ms) to accomplish that:
        >
        > Frame 0: request to send the data to peripheral
        > Frame 1: data transmitted on the bus
        > Frame 2: data received by peripheral and request to send response data to host
        > Frame 3: data transmitted on the bus
        > Frame 4: data received by host
        >
        > As you see, only 250 consecutive request/response cycles are possible. The
        > situation improves with USB2.0 microframe, which is 125us long. That allows for
        > 0.5ms cycle, but you need USB2.0 high speed hardware like Cypress CY7C680xx
        > microcontrollers.
        >
        > Paul.
        >
        > ---------------------------------------------------
        > Date: Mon, 17 Jan 2005 22:30:18 -0600
        > From: Jeff Sampson <jsampson@...>
        > Subject: Re: Re: I/O device, Collaborative project
        >
        > Since no one has said "no, there really is a 50hz refresh problem", then
        > I'll assume it is not a problem.
        > ......
        >
        >
        > Visit the SRS Website at http://www.seattlerobotics.org
        > Yahoo! Groups Links
        >
        >
        >
        >
        >


        --
        Jeff Birt
        Electronics Engineer
        Integrated Systems Facility
        University of Missouri - Rolla
        573.341.6058
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