I read that I can setup analog inputs as digital, but I seem to be having an issue. I use digitalRead to read the four inputs of an L4 RF Latching Receiver on A0, A1, A2, and A3, but the A0 input always seems to stay HIGH, resulting in two HIGH inputs. Since the receiver only puts one pin high at a time, and it seemed to work fine using digital inputs, perhaps the issue is related to the digital interpretation of the analog input? I haven't been able to fix it.
By the way, the reason I'm using the analog inputs is because I'm controlling a motor via an Adafruit Motor Shield stacked onto an Arduino Uno R3 and the Motor Shield AFMotor library requires all of the digital pins for operation. (Setting the L4 up on the Motor Shield's digital pins worked, but the motor wouldn't run...) So, I'm using the A0-A3 analog inputs and the +5 and GND signals from the Motor Shield through-hole region.
Arduino Reference for DigitalRead - http://arduino.cc/en/Reference/DigitalRead
Any ideas what I might be doing incorrectly?