Re: [mh] Serial port trigger?

[Ralph M. <ral...@gm...>]

On 6/13/07, Rick Bolen <rb...@ca...> wrote:
> > "hardware signalling" you could use the DTR and CTS lines to communicate -
>
> I've read about this technique recently. Seems clever and economical, but I
> was wondering about its' immunity to induced interference (e.g, nearby
> lightning discharge, power surges etc)? Seems like it would be susceptible
> to state change. Can that kind of thing be debounced?

There's another possible problem - if you're relying on the serial
port for a data stream, such as 1-Wire, you might find that the stream
halts if you play with the status lines.  They are, after all,
intended to stop and start the character flow through a modem...

I've had this experience on some old hardware - even an ASCII terminal
wouldn't work with just the data pins & ground connected.  As soon as
I wired the correct pins high, the login prompt appeared.

That's not to say you *can't* use those pins - just that the serial
port may not function as a serial port if you do.

Ralph Mitchell