Colin wrote: > Hello, > > I have configured emc for parport setup as output, however when I measure > the voltages on the input pins 10,11,12,13 and 15 I find that they are > already high eg 5V. Can I set the pins to 0V and then drive them high by > signals? > Wiring to input pins on a parport was touched on only a few days ago:
On Mar 30, replying to someone who asked about wiring a pause button, I wrote: > If you tie the other end of the switch to +5, then > closing the switch will pull the parport pin high. You need > something else to pull it low when the switch is open. If you tie > the other end of the switch to ground, then closing it will pull > the parport pin low. Since A) many parports already have pullups, > and B) there isn't a convenient source of +5 on the parport, its > usually easier to hook a switch between the parport pin and ground. > > The above is NOT an EMC specific issue. How to hook a button to a > parport is basic fundamental knowledge for using a PC to control > anything. This information is on the web - for example > http://www.epanorama.net/circuits/parallel_output.html > Inputs are addressed in the section "Input Circuits" about 3/4 of > the way down the page. Electrically, connecting a pushbutton or > toggle switch is no different than connecting a limit or home switch. The reason you are seeing 5V on your parport input pins is because they have pullup resistors. If you wish to drive them with simple switches, it is best to connect the switch between the input and ground. If you wish to drive them with logic gates, just do it. A logic gate actively drives both high and low, and has no trouble overcoming a pullup resistor. If you don't know what a pullup resistor is, google and wikipedia are your friends. Wikipedia has a decent article, which also links to a nice page here: http://www.seattlerobotics.org/encoder/mar97/basics.html Regards, John Kasunich ------------------------------------------------------------------------- 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 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
