Is there any way to have direct digital writes similar to PORTD but with additional pins?
...My question is - can this be generalized to 10 bits or higher? ...
Yes you can have a ladder like this for any resolution you want (4, 5, 8 ,10, 16 and so on).
QuoteYes you can have a ladder like this for any resolution you want (4, 5, 8 ,10, 16 and so on).The problem with going to higher bit counts is the resistor matching. The more resistors you use the tighter they have to be matched to each other. With normal 1% resistors you will not get more than about 6 bits and maintain monoticity.