dspic33E series ADC Buffer size and Sampling count confusion
I think there is a contradiction between dspic33E Family ADC Reference manual and MCU dspic33EP512MU810 datasheet. I have attached an image below that correctly shows the SMPI bit details in ADxCON2 register.

The image attached is the correct one and it can be found in MCU datasheet. and I have verified it with Microchip. FRM shows the wrong information. Have updated this mismatch to Microchip team.