Hello fellow gEDA users, I have a general hardware design question not specific to a particular design tool, so please forgive me for OT.
Suppose I have an RS-232 output (DTR in my case) that is always asserted. Is it acceptable to drive it directly from the +12V supply (through a resistor I presume) instead of using a proper RS-232 driver with a pegged input? The reason I want to do this is because I'm using a quad driver chip and all 4 drivers are used for non-static signals, so I would much rather avoid using another quad driver chip just to use only one section of it with a pegged input to put out an asserted DTR. So is there anything terribly bad/spec-violating/unsafe about driving an always-asserted RS-232 output directly from the +12V supply through a resistor, or is that perfectly OK? What should the resistor value be? Or should I use something more fancy like a PTC resistor acting as a resettable fuse protecting against external shorts? TIA, MS _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
