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RE: X10 Schema best-practice
- Subject: RE: X10 Schema best-practice
- From: Kevin Hawkins
- Date: Sat, 06 Mar 2004 15:57:00 +0000
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<DIV dir="ltr" align="left"><FONT
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class="500353615-06032004">Sorry this is
not within the message context below but it looked
lost....</SPAN></FONT></DIV>
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<DIV dir="ltr" align="left"><FONT
face="Arial" color="#0000ff"
size="2"><SPAN
class="500353615-06032004"> I had some
similar decisions with my C-Bus lighting connector - should I
expose it as a C-Bus schema or a more general lighting schema - I actually
implemented both allowing for C-Bus 'groups' which are the end devices to
be exposed and controlled but also named devices etc.
</SPAN></FONT></DIV>
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<DIV dir="ltr" align="left"><FONT
face="Arial" color="#0000ff"
size="2"><SPAN class="500353615-06032004">One
of the issues with say exposing X10 as a lighting or appliance control
system is that a xAP connector has no real way of knowing what devices are
out there in an X10 world (discovery) and even then not knowing their
capabilities or being able to determine state. I think there is a
role for both as an interim solution but the goal of xAP is very much to
abstract the hardare to the functionality. Certainly having an
X10 specific schema makes it much easier for an existing software
application that works with X10 to implement this via
xAP.</SPAN></FONT></DIV>
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<DIV dir="ltr" align="left"><FONT
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size="2"><SPAN class="500353615-06032004">On
the status side I dont think there was any intention that this should be
mandatory and as the hardware mostly isnt capable its not really possible
either. There is potential taht a xAP connector for X10 could track the
stauts of a device by monitoring the X10 data seen on the network and hence
report a 'best guess' but this is problematic with missed data, relative
dims and of course manual intervention. Perhaps teh connector could return
a flag to say 'best guess' - which really reflects X10's failings in my
mind. Of course if a device did trul support hardware status responses you
could do it correctly.</SPAN></FONT></DIV>
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<DIV dir="ltr" align="left"><FONT
face="Arial" color="#0000ff"
size="2"><SPAN class="500353615-06032004">The
possibility of xAP within an MSS100 is very interesting - perhaps the
ability within a schema to send and receive serial packets from the
serial port and to also toglle/read the handshaking lines. This
would allow simple serial devices to be 'xAPped' instantly - eg a HiFi
amplifier. You could also interact more directly with teh MSS100 firmware
to provide for character/timed thresholds and automatic handshaking in
certain modes. There is an SDK available for the MSS100 (freely
downloadable) allowing you to code in ANSI C - although I ahve written some
basic 'hello world' type applications that is as far as I got but it would
create another market for these devices.
</SPAN></FONT></DIV>
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<DIV dir="ltr" align="left"><FONT
face="Arial" color="#0000ff"
size="2"><SPAN class="500353615-06032004">You
may be aware also Johan that I sourced a number of second user MSS100's at
a great price (£49) to offer to HA enthusiasts - I have even set up a US
source for them too and have sold a couple of hundred thsi way. My
intention at that time was to look at the embedded xAP possibility as it is
a natural fit. But as ever time and intentions often conflict.
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<DIV dir="ltr" align="left"><FONT
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class="500353615-06032004">Kevin</SPAN></FONT></DIV>
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<DIV dir="ltr" align="left"><FONT
face="Arial" color="#0000ff"
size="2"><SPAN class="500353615-06032004">Just
in case anyone here is wondering what an MSS100 is ... it
provides the hardware to Ethernet enable standard RS232 serial devices so
they can be connected over an IP network rather than need a serial cable.
Virtual COM port drivers exist for
Windows.</SPAN></FONT></DIV>
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<HR tabIndex="-1">
</DIV>From:</B> Johan Helsingius [mailto:yahoo@xxxxxxx]
<B>Sent:</B> 06 March 2004 15:29<B>To:</B>
xAP_developer@xxxxxxx<B>Subject:</B> RE: [xAP_developer] X10
Schema best-practice</FONT></DIV>
<BLOCKQUOTE>
<DIV></DIV>At 12:16 06/03/2004 +0000, Edward Pearson
wrote:
<BLOCKQUOTE class="cite" cite
type="cite"><FONT face="arial"
color="#0000ff" size="2">I'm writing a CM12
connector as an exercise in using the xAP framework. I'm trying to decide
on whether it should present its xAP interface as an X10 schema or a
lighting schema (or both). My request for X10 best-practice was to see if
there was anything generally agreed out there already that I could rapidly
implement so the connector would be useful for folks other than myself.
</FONT></BLOCKQUOTE>Well, seems all previous efforts have been
based on the "expose X10, warts and all" kind.But I think it kind
of defeats the whole purpose of xAP.
<BLOCKQUOTE class="cite" cite
type="cite"><FONT face="arial"
color="#0000ff" size="2">Personally I think X10
stinks so I'll not be going to the trouble of designing a schema for it
myself, I'd rather spend the time thinking about what a basic lighting
schema might look like and prototyping around
that.</FONT></BLOCKQUOTE>Exactly!X10 is a good example of what
happens when hardware engineers tryto design a communications protocol. OK,
I can understand that true 2-waywith acknowledgements would have required
additional hardware, but the lack of an absolute dim command is just
criminal! And the braindeadseparation of address and command into separate
messages...
<BLOCKQUOTE class="cite" cite
type="cite"><FONT face="arial"
color="#0000ff" size="2">There are some arguments in
favour of an X10 schema such as this:-</FONT><FONT
face="arial" color="#0000ff" size="2">X10
has become a very broadly used and well understood protocol to the extent
that many home automation contollers (hardware device or software package)
use it as the model they reveal to the end user - this is sad but
true. Normally these devices connect to the X10 adaptor
(CM12/CM11) by directly attaching it to a serial port - having an X10
schema is a way of enabling network-connected X10 adaptors that could be
used without direct connection. So in world where change is incremental is
seems advantageous to have an X10 schema to allow gentle migration for
existing products towards xAP.</FONT></BLOCKQUOTE>OK, so yes,
maybe a "legacy" x10 schema is called for - but then maybe
we just need a generic "pass bytes" schema. But for new
applicationswe need a function-based schema - I really don't want all my
componentsto have to know about the horrors of X10.
<BLOCKQUOTE class="cite" cite
type="cite"><FONT face="arial"
color="#0000ff" size="2">An example of a network
enabled X10 interface would be a CM12 plugged into a Lantronix MSS100
(<A href="http://www.lantronix.com/products/ds/mss100/index.html";>http://www.lantronix.com/products/ds/mss100/index.html</A>)
where the MSS100 had been customised to talk
xAP.</FONT></BLOCKQUOTE>Right. But can you get Lantronix to
implement xAP? I might be able to get these guys to implement it, as I'm an
investorand on their board:<A href="http://www.violasystems.com/";
eudora="autourl">http://www.violasystems.com/</A>Their
eserv is pretty similar to the Lantronix box.<
A href="http://www.violasystems.com/device_servers.php";
eudora="autourl">http://www.violasystems.com/device_servers.php</A>
<BLOCKQUOTE class="cite" cite
type="cite"><FONT face="arial"
color="#0000ff" size="2">It is true that very few
X10 devices report status. But there are plenty of applications where it's
useful to be able to receive X10 messages - the one I'm interested in is
receiving X10 messages from an IR7243 controller that picked up a
transmission from a Pronto remote and passes them into the xAP
world.</FONT></BLOCKQUOTE>Absolutely. But the way I read the
drafts they *required* support forstatus reports.</BLOCKQUOTE><!--
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