[PLUG] Serial Port Programming

Richard C. Steffens rsteff.l at comcast.net
Sun Oct 31 00:43:45 UTC 2004


On Thursday 28 October 2004 9:05 pm, Terry Griffin wrote:

> The CP290 is an odd beast. It communicates at 600 baud but it requires
> a one millisecond delay between each transmitted byte. It's that delay, if
> poorly implemented, that breaks when you move CP290 control software
> up to a faster PC.

So I noticed in the CP290 manual.

> I think your best bet is to find that delay mechanism 
> in the code and either tune it for your PC or fix it properly for all PCs.
> I don't think the compiler warning is the source of your problem.

I'll see if I can figure that out.

> I'm in the middle of a from-scratch implementation of X10 control software
> using Python and pyserial. The CP290 portion is working more or less
> though there's still a lot of clean-up to do before I'm ready to thrust it
> on to the world. The one millisecond delay is implemented using Python's
> time.sleep() function. This works fine on my development box. It will be
> interesting to see what happens when it's exposed to other computers.

I'd be happy to give it a shot on a couple of my machines:

200 MHz Pentium MMX running RH 7.0
Thinkpad 390X (400? MHz Pentium) Running RH 8.0

> I'm also planning for the CM11A and CM17A controllers. I have nothing at
> all for those yet.

I've got another serial interface with the IBM Home Director logo on it, model 
HD11A, which I'm guessing is the same as the CM11A. It never worked with the 
Windows software that came with it. I never got around to sending it back. 
Seems to me there's an RF remote control with it, too. I'll have to dig into 
the back of the shelf it's stored on.

Again, if you're looking for alpha or beta testers, I'm game.

-- 
Regards,

Dick Steffens
http://home.comcast.net/~rsteff/



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