On Thu, 24 Jan 2008 01:01:13 +0200 "Dumitru Stama" wrote: > I think i will try to test the ladder using some jumper switches > instead of PIC pins, this way at least i will know is not a "not enough > current" issue. But that is very easy to discard as a problem... Simply put out all ones, and measure the voltage in each output pin. It should be very near VCC. If that's ok, DO check the configuration. If you have the one intended for an Opamp amplifier (first link I sent), you cannot measure it without the opamp functioning (the opamp is needed to present a short to the R/2R network). The second configuration is slightly different, and should not be loaded at all (if you have an amplifier at the output, be sure it has its supply connected, and that the input can handle the 0-VCC swing of the R/2R (ie., don't supply it with VCC), else the inputs will load the network and produce things like you describe. John -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist