Re: CM11A gets 'stuck' (and fix)

[Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx>]

Hello Neil,


> Well it looks like I've found the source to a recent spat of control
> problems. It's my new laser printer. Here's what happens: when the
> laser printer starts up there is a sudden dip in the power because of
> the laser heating up (or at least some heating element is heating up).
> This causes my CM11A to get stuck. I can talk to it like when I send
> commands but the commands never get sent. Normally when the CM11A
> gets stuck I can just use another device to send an X10 command. This
> usually unsticks the CM11A. That doesn't work in this scenario. To fix
> this problem you must unplug the CM11A and plug it back in. Then it
> begins to work fine. Both the CM11A and the printer are on the same
> circuit. I'll have to change that. One more thing to note, the CM11A
> doesn't get hot. I left this problem over night and the CM11A is cool
> as it normally would be.
>
> So the short of it is that the CM11A doesn't like brown outs.
>

Those are the typical symptoms of what us analog/mixed signal guys call
a "dirty reset". Happens a lot, even with expensive equipment such as
the multi-purpose hub machine here in my office. Somehow the art of
designing a proper reset hasn't sunk in :-(

Even some micro controller data sheets suggest a simple RC scheme for
the reset. That isn't going to cut it for brown-outs.

--
Regards, Joerg

http://www.analogconsultants.com