From: Rick B. <rb...@ca...> - 2007-06-13 17:16:00
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> 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. That's right. You're sacrificing the data xfer capability of a serial port to be a simple switch. > -----Original Message----- > From: mis...@li... > [mailto:mis...@li...]On Behalf Of > Ralph Mitchell > Sent: Wednesday, June 13, 2007 1:01 PM > To: The main list for the MisterHouse home automation program > Subject: Re: [mh] Serial port trigger? > > > 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 > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > ________________________________________________________ > To unsubscribe from this list, go to: http://sourceforge.net/mail/?group_id=1365 |