In Single Conversion mode: The channel should be selected before starting the conversion. The channel selection may be changed one ADC clock cycle after writing ‘1’ to the STCONV bit.
In Free-Running mode: The channel should be selected before starting the first conversion. The channel selection may be changed one ADC clock cycle after writing ‘1’ to the STCONV bit. Since the next conversion has already started automatically, the next result will reflect the previous channel selection. The subsequent conversions will reflect the new channel selection.