From: Brian W. <bw...@ir...> - 2007-01-18 13:55:05
|
On Wednesday 17 January 2007 19:03, tim...@co... wrote: > Hi Dave, > > Yes, I agree, KISS. Funny thing is I was just revieving > our customer schematics and they used a switch > connected to a resistor to ground without pull up. > I tried to tell them it would not work, but they blew > me off suggesting software people should not be > looking at schematics. ;-) > Funny, when the tech I have adding the button on asked about the resistor to ground initially and button setup I just said don't worry. Maybe SW people ought not be doing EE work :) > > Tim > > BTW: Since this question has been asked more than > once on this forum, maybe we sould do a wiki page? > > -------------- Original message ---------------------- > From: "Dave Hylands" <dhy...@gm...> > > > Hi Tim, > > > > > Would it be possible to have a switch connected to ground > > > via a resistor, than program the gpio as output, program it > > > high then enable the edge detect interrupt to detect a falling > > > edge? > > > > Programming the edge detect interrupt requires that it be configured > > as an input. You really don't ever want to run the risk of having the > > pin configured as an output when the input might be connected to a > > different voltage (say the switch is closed). > > > > Since you'd need a resistor anyways, why not just connect it up in the > > conventional manner? > > > > Here are the two conventional ways of connecting a switch. > > > > 3.3v ---\/\/\/\/-----+-----o/ o----- Gnd > > > > GND ---\/\/\/\/-----+-----o/ o----- 3.3v > > > > Where the + goes to the input. > > > > -- > > Dave Hylands > > Vancouver, BC, Canada > > http://www.DaveHylands.com/ > > > > ------------------------------------------------------------------------- > > Take Surveys. Earn Cash. Influence the Future of IT > > Join SourceForge.net's Techsay panel and you'll get the chance to share > > your opinions on IT & business topics through brief surveys - and earn > > cash > > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > > _______________________________________________ > > gumstix-users mailing list > > gum...@li... > > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share > your opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users |