>From: Patrick J >Reply-To: pic microcontroller discussion list >To: PICLIST@MITVMA.MIT.EDU >Subject: Re: different approach to keyboard scanning? >Date: Thu, 10 Apr 2003 02:11:28 +0200 > > >Use the A/D inputs of the PIC instead ? >(then you can define your own 0 and 1 voltage levels in software) Unfortunately, the PIC I use doesn't have A/D, and besides, the number of A/D inputs would be impractical. > >Tho I am not sure why you want to do this in the first place. It is quite >common >to read keyboards in X-Y fashion. Just not with diodes in the juncions as >you do. Well, to read a 3x4 keyboard you normally need 7 I/O lines (unless you add external chips). The way I want to do it would only need 4 lines. I also need n-key rollover, so diodes are going to be necessary at the junctions in any case. I just wanted to see if I could get by with just those diodes and a little cleverness. _________________________________________________________________ STOP MORE SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu