There's a tricky method using a set of analog switches to charge a
capacitor from the voltage source, disconnect both legs from that
source and connect it to your ADC.

Can also offset the ground of the measurement using a DAC or PWM.

Add protective series resistors in case the analog switches aren't
left in the right state.

--=20
James Cameron
http://quozl.linux.org.au/
--=20
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