[Coco] [Color Computer] X10 driver

[Gene Heskett]

On Monday 25 June 2007, George's Coco Address wrote:

>The CP290 is indeed an RS232 unit. It is also out of production. I've found
>on the net that it also had issues with it's clock frequency and the
>oscillator for the data that it puts on the power line.
> Since the CM11A is readily available and inexpensive, there's no need for
>any other timer that I know of.
>
>George

I've heard of the poor clock in some units.  I have 2 cm11a's here, but one 
got a bit flaky (weak tx signal on the powerline) several years back & got 
swapped out.  The remaining one has worked quite well now for 6 or 7 years, 
and its about 15 years old now.

Clockwise, it gets its internal clock reset to system time for EST/EDT 
whenever I reboot and the script restarts heyu.  Or the cm11a will request a 
clock reset on recovery from a power failure.  The delay times in reading the 
clock back out are several seconds so the ultimate accuracy is limited by 
that.  But even with 2 weeks to a month of uptime, I've never noted the 
cm11a's time as being off more than 10 to 30 seconds.  It has a backup 
battery(s) in it, and keeps decent, not wrist watch quality time during the 
power failures.  I have nearly everything on a ups here except of course the 
cm11a, so I can query it while the local wall power is out.

Its a decent unit, at a decent price, and relatively easily controlled.  The 
comm protocol does take some shortcuts because its actual interface is via a 
4 wire cable adaptor that plugs into a db9 connector.  So you can't just 
shove an unlimited amount of data at it without getting out of synch.  Proper 
observation of the software handshaking portion of its protocol is a must.

-- 
Cheers, Gene
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