Hopefully just a quick one; I am using an Arduino Nano for my project, I have the following attached;
Pins 11, 12, 13 - 2x MAX7219 daisy chained to drive 11x 7 segment displays
Pins 8, 7, 6, 5 - 2x 74HC165's daisy chained to read buttons
Pins Pins 4, 3, 2 - 2x 74HC595's daisy chained to drive 16 LED's
This leaves me with digital pins 9 and 10 free, as well as RX0 and TX1, and all of the analog pins. I want to use an SD card module which will require 4 pins.
My Question: Can I use the Analog pins as digital pins to drive some of these modules? or do RX0 and TX1 act as digital pins?
I'm happy to start the reading to see the 'how' this would work, but don't want to waste my time digging if it's not possible. I understand that if using analog as digital I may need to reshuffle the pin allocations potentially (for MISO and MOSI compatibility).