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Re: Can I interface the NSLU2 to an EIA-485 bus?

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  • Sam
    ... a ... Just an aside if you dont know already - The NSLU2 is discontinued, and therefore no longer being produced So the chances of being able to source
    Message 1 of 4 , Jun 13, 2008
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      --- In nslu2-general@yahoogroups.com, "Anssi Porttikivi" <app@...>
      wrote:
      >
      > If I have some home automation equipment that is controlled via a
      > proprietary protocol on top of serial EIA-485 (RS-485) bus, can I do
      a
      > hardware hack to the NSLU2 to interface to that? I am actually
      > planning a commercial product based on this, and we have some
      > resources to buid it, if it makes sense.
      >
      > Or does anyone have any ideas of another cheap, general purpose, easy
      > to program platoform for controlling home automation?
      >

      Just an aside if you dont know already - The NSLU2 is discontinued, and
      therefore no longer being produced

      So the chances of being able to source many for a commercial product
      for the longer term are quite slim

      Just a heads up!
    • John
      ... You can add a USB-to-RS-485 hardware dongle to support RS-485 from a slug. The one that I use is the USB-COMi-SI . You don t mention which proprietary
      Message 2 of 4 , Jun 13, 2008
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        On Fri, Jun 13, 2008 at 10:15:37AM -0000, Anssi Porttikivi wrote:
        > If I have some home automation equipment that is controlled via a
        > proprietary protocol on top of serial EIA-485 (RS-485) bus, can I do a
        > hardware hack to the NSLU2 to interface to that? I am actually
        > planning a commercial product based on this, and we have some
        > resources to buid it, if it makes sense.

        You can add a USB-to-RS-485 hardware dongle to support RS-485
        from a slug. The one that I use is the "USB-COMi-SI".

        You don't mention which proprietary protocol but it is likely
        that you would be responsible for the software to implement it.
        You can control the RS-485 I/O on a slug via programs written in a
        language of your choosing: C or Python or whatever.

        > Or does anyone have any ideas of another cheap, general purpose, easy
        > to program platoform for controlling home automation?

        There are lots of cheap single-board computers with good serial I/O
        support. What is unusual about the slug is not its feature set but
        that it comes complete with power supply and a nice consumer-friendly
        case.
      • tbering2002
        ... You could also connect a TTL to RS-485 transceiver chip to the onboard serial port on the NSLU2. That would be a pretty good option, as it would let you
        Message 3 of 4 , Jun 16, 2008
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          --- In nslu2-general@yahoogroups.com, "Anssi Porttikivi" <app@...> wrote:
          >
          > If I have some home automation equipment that is controlled via a
          > proprietary protocol on top of serial EIA-485 (RS-485) bus, can I do a
          > hardware hack to the NSLU2 to interface to that? I am actually
          > planning a commercial product based on this, and we have some
          > resources to buid it, if it makes sense.
          >
          > Or does anyone have any ideas of another cheap, general purpose, easy
          > to program platoform for controlling home automation?
          >

          You could also connect a TTL to RS-485 transceiver chip to the onboard
          serial port on the NSLU2. That would be a pretty good option, as it
          would let you use the NSLU2 to prototype your code, and then switch to
          a different platform when the concept is closer to production.

          Warning: at least on my NSLU2 units, the boot loader listens for
          traffic on the serial port at startup. As such, with a half-duplex
          serial connection, the NSLU2 will hear its own traffic and abort the
          boot process. You will need to gate Rx inputs to the slug to a
          disabled (low) state for the first section of the boot process. This
          is easy enough to do, if you know to do it.
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