Hi,
I guess you COULD use ADCIN but it kind of defeats the purpose of the interrupt since it is a self timed command.

When using ADC interrupts you basically set the GO/DONE bit to start the converstion and the interrupt fires when the ADC conversion is done. If you then use ADCIN in the interrupt handler it would perform another, self-timed, conversion which, again, kind of defeats the use of interrupts in the first place.

The idea is to start the conversion and then either go to sleep or go do something important while the ADC does its job. The interrupt fires when the conversion is complete and you go grab the result by reading ADRESH/ADRESL register pair.

/Henrik.