Quote Originally Posted by passion1 View Post
Could you please suggest values for the decoupling caps between VDD and VSS and the cap on RA3?
I'd use 100 pF or so (5 time periods * 100e-12 * 2000 = 1uS, way less than your 50uS sample time). This is not your problem either, my thought was you might have had something too big on there slowing the charge. Adding a cap here will help keep the answer solid, but at 8 bits, you should not have a problem without for now.

the rails?