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[JeffVolp]

Some of you have written code to deal directly with the CM11A.  I have a question regarding the extended code protocol. 

The extended code document defines 4 bytes sent to the CM11A to transmit an extended command:

   Byte 1:  Header (only defines the transmission type)
   Byte 2:  Code (just contains the housecode and 0111 extended data type)
   Byte 3:  Data (8-bit random data)
   Byte 4:  Command (8-bit extended command function code)

Nowhere in those 4 bytes is the unit code defined.  However, there is a line in the document regarding the code byte that says:

“Again, the housecode must be the same as any previously addressed modules…”

Does anyone know if there is an error in the protocol document where the code byte actually contains the unit code, and the house code is lifted from the previous command?  If not, where does the unit code that is part of the extended transmission come from?

Jeff

[JeffVolp]

I may have answered this myself by continued web searching.  I found an updated protocol document version 1.6 (last revision 2003) that shows the CM11A serial extended data protocol as being 5 bytes.  The additional byte contains the unit code in the least significant 4 bits.  I will assume this is correct unless otherwise advised.

(FYI - since the CM11A has long been discontinued, I've been looking at a possible XTB version that supports the direct transmission and reception functions needed by some high-end automation software.)

Jeff

[Brian H]

A XTB with CM11A functions sounds like a good thing.
We see messages here on where they can still be found.

[Brandt]

Would this mean a direct CM11a replacement for us heyu users?


regarding the unit code...the log entries look like this:

08/17 19:40:20  snda addr unit       4 : hu M4  (garage_dusk)
08/17 19:40:20  snda func           On : hc M


no sure if that helps or not...

[JeffVolp]

Would this mean a direct CM11a replacement for us heyu users?

I'm not sure about that.  It depends on whether heyu uses more than direct transmission and reception, which would not be supported.

This may not happen at all.  It is just something I am considering as an offshoot of some other work I am doing.  Just like that proposed X10 power monitor.  That never went any further than the initial breadboard because it became obvious it would be too expensive to produce.  That may happen here too because of the limited market for something like this.  I am only considering it because a number of people thought the digital interface on the XTB-IIR could connect to a PC serial port.

Thanks for the log, but I needed to confirm the actual bytes sent between the PC and the CM11A.  The original X10 protocol document did not include a unit code, but the revised document (updated by someone who is a regular on this board) includes an extra byte with the unit code.

Jeff

[Brandt]

Well, if you're looking for a market, I'd pay for an X10 horizontal mini-blind tilter or 5 that would allow x10 and local control.   :-)

I was going to attempt to do this, but no extra time and not very well versed in electrical design

My idea was to use one of those X10 camera power supplies with an always on for local control with tactile buttons and the on and off for x10 control. Then I was thinking to mount a servo or stepper motor on the window sil and have the installer buy a longer tilt wand and cut it to length to fit into the servo on the sil. Then mount the electronics in a tiny white telephone junction box under the sil which there is usually a receptacle under a window also.

[JeffVolp]

Well, if you're looking for a market...

Not really looking for a market.  I've been turning down consulting work because of a lack of time.

About the only time I get a day away from this stuff is when I go off hiking - have to smell the roses before they all shrivel up and die...

Jeff