ADC measurement and GPIO output on the same pin

[czarlz]

Does anybody have any experience in using exactly the same pin as an ADC input and a communication GPIO (out), as two alternating functions? Would it be possible to set? If so, can the GPIO drive the small capacitor that is typically needed for an SAR ADC? The communication speed can be slow (9600 or so).

Many thanks!

[cwunder]

If the ADC input is also on a pin that has a digital GPIO (like P0 or P33 for TC3x) then yes you can read it both via the Px_IN or with an analog conversion. When you have the pin configured as a digital output the analog reading is limited to where the output driver voltage is.