Arduino Analog Port for Input and Output

Hello everyone,

I require 3 analog input pins (A0, A1 and A2) for reading analog sensor values and the remaining 3 (A3, A4, A5) as digital outputs. The digital outputs are given to an Analog MUX. The analogRead() will be called frequently, just after setting the digital outputs. Will the switching of digital pins affect the analog readings taken? If yes, then what changes should I make, other than adding a delay before calling analogRead()?

Thanks in advance.

Will the switching of digital pins affect the analog readings taken?

No.

If yes, then what changes should I make, other than adding a delay before calling analogRead()?

If possible, keep current lower for 3 digital pins, distributing high load on D(0..7) or B(8..13) ports.

Can it be done by adding resistors in series? What value will be appropriate?

Depends on a load (LED, logic inputs, transistors etc). 20 mA is long term maximum