AMay, I personally would tend to use a constant current source with the RCTIME function. That way you can measure the timing between 2 points with the cap charging at a fixed rate (much more linear). Remember that the resultant range can not be greater than 0 to 65535 so you will probably have to use different current levels to maintain accuracy over large ranges 100Pf to 100 uF. I have used this methode for measuring the backup storage of airbag modules capacitors in production equipment with great success. LOL

Dave Purola,
N8NTA