if what you are intending is "true" 10 to 1 bit round off, ie the threshold is in the middle, digital input wont do it as it will go HI 1 by the time the input reaches > 0.3V or 1V or so. if you are using 5V rail and you want to round off to HI 1 at 2.5V (threshold is in the middle) you can leave the ADC ON and only read the 5 higher bits of ADC register, if its not zero then you can assign a 1bit register as 1.
if HI(ADC, 5) then myVar = 1; else myVar = 0;