> Also don't you need a minimum of 2V(?) from Vref- to Vref+ > even if they are otherwise within range? Correct. But the only thing I need from the A/D is resolution and monotonicity, so I just tried with this smaller range and it seems to be OK. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: www.voti.nl/hvu -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist