On Mon, 8 Nov 1999 16:51:22 -0700 Dwayne Reid writes: >> When I go to read all 3 channels (in a loop), the value on the >individual >>channels >> seems to affect the others. >> Example: If all channels are set for full scale, then all will >read 255. >>But if I then >> gradually decrease one channel input, one or sometimes both the >other >>channels >> will also decrease. > >Yep - same answer as listed a few messages earlier - increase the >amount of >time you wait after changing input channels BEFORE you start your next >conversion. Mchip is hopelessly optimistic when they say 20 uS - I >allow at >least 80 - 200 uS. > I have no problem with 20uS. One thing to watch out for is the impedance of the source driving the analog input. For a 16c74, Microchip recommends a maximum of 10K. I use a maximum of 2.5K (a 10K pot driven by +5V and ground). Besides generating an offset voltage due to bias current, a high source resistance will slow the charge time of the A/D holding capacitor. Harold Harold Hallikainen harold@hallikainen.com Hallikainen & Friends, Inc. See the FCC Rules at http://hallikainen.com/FccRules and comments filed in LPFM proceeding at http://hallikainen.com/lpfm ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj.