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[ZarkWizard]

Hi All,

I finally got around to working on trying to code an interface for my CM11A.  One of the things I noticed is the interface keeps polling me with the 0xA5 code noting that power went out and it has no time.

The bit layout for the time is :
The PC must then respond with the following transmission

Bit range   Description
55 to 48   timer download header (0x9b)
47 to 40   Current time (seconds)
39 to 32   Current time (minutes ranging from 0 to 119)
31 to 23   Current time (hours/2, ranging from 0 to 11)
23 to 16   Current year day (bits 0 to 7)
15   Current year day (bit 8)
14 to 8      Day mask (SMTWTFS)
7 to 4      Monitored house code
3      Reserved
2      Battery timer clear flag
1      Monitored status clear flag
0      Timer purge flag

I don't get bits 7-4.  Also when would you use bits 2 - 0.  Does the Timer purge flag remove macro timers?  I would assume you set 2 when you set the time.  I have no idea what bit 1 does.

Any clarification would be greatly appreciated.

Thanks.

[Charles Sullivan]

The CM11A has internal registers which store the state of modules on a single housecode.  Bits 7-4 let you program which housecode to use.

You would set the Battery timer clear flag initially, and then only when when you change the battery in the CM11A.
The Timer purge flag clears timers with a delay which has started but not yet executed.
The Monitored status clear flag clears the above mentioned internal registers.

Note that the CM11A Protocol document on the X10 website lists bits 0-2 incorrectly.  For a corrected copy of this document, see http://www.heyu.org/docs/protocol.txt

[ZarkWizard]

Thanks for the updated docs.  I am sure they will help with writing the interface.

Although I am still curious about the house code...

Are there multiple clocks to be set up for each house code?  eg A-P?  Do I have to set the clock for every house code?    If I read your message right it would seem to be the case. 

So if I wanted to set the clock for house code A, and the time and date are : Tues Sept 2 2008 : 10:15:33am I'd be looking at something like :

Sending the characters representing:
0x9b     
0x21  (33 seconds)
0x0f  (15 min, why does it say up to 119 min?)
0x0A (10 hour (am))
0xF6 (Sept 2nd 246th day this year - including leap)
0x00 (carry bit for days 256-365(6)  1 = Day Byte + 255)
0x04 (For Tues assuming bit flags == the day  1=Sun, 2=Mon, 4=Tues, 8=Wed, 16=Thurs, 32=Fri, 64=Sat)
0x67 (Bit settings based on House Code A + Reserved = 0, Timer Purge = 1, Batt Clear = 1, Monitor Stat Clear = 1  [Binary 01100111])

So I would basically send the above sequence of 8 bytes to set the time for House Code A, and do you have to repeat that for House Codes B-P?

Thanks for the assistance.

[Charles Sullivan]

Thanks for the updated docs.  I am sure they will help with writing the interface.

Although I am still curious about the house code...

Are there multiple clocks to be set up for each house code?  eg A-P?  Do I have to set the clock for every house code?    If I read your message right it would seem to be the case. 

No, there's only one clock.  The CM11A internal registers can store the state for only a single housecode.  The CM11A can receive signals from all housecodes but except for the monitored housecode these have to be processed by your PC when received.

So if I wanted to set the clock for house code A, and the time and date are : Tues Sept 2 2008 : 10:15:33am I'd be looking at something like :

Sending the characters representing:
0x9b     
0x21  (33 seconds)
0x0f  (15 min, why does it say up to 119 min?)
0x0A (10 hour (am))

Byte 3 is the hours/2 ( = 5 ) and byte 2 is the remainder minutes ( = 15 min).  (If the time were to be 11:15:33AM, Byte 3 would be 5 and byte 2 would be 75 min.)

0xF6 (Sept 2nd 246th day this year - including leap)

The day count starts with Jan 1 = 0, so Sep 2, 2008 would be day 245.

0x00 (carry bit for days 256-365(6)  1 = Day Byte + 255)
0x04 (For Tues assuming bit flags == the day  1=Sun, 2=Mon, 4=Tues, 8=Wed, 16=Thurs, 32=Fri, 64=Sat)

There's only one byte here.  The MSB of the day count is the high bit in the weekday bitmap byte.

0x67 (Bit settings based on House Code A + Reserved = 0, Timer Purge = 1, Batt Clear = 1, Monitor Stat Clear = 1  [Binary 01100111])

That's correct.

So I would basically send the above sequence of 8 bytes to set the time for House Code A, and do you have to repeat that for House Codes B-P?

No, there's only one clock, as described above.  And there are only 7 bytes to send.

The CM11A will respond by returning the 8-bit checksum of bytes 1 through 6.  You should then send 0x00 and wait for the CM11A to respond with 0x55 before sending further commands.