Pin Configuration and IO Multiplexing : Arduino / ATmega328p - Arnab Kumar Das
Amazon.com: ELEGOO Nano Board CH 340/ATmega+328P Without USB Cable, Compatible with Arduino Nano V3.0 (Nano x 3 Without Cable) : Electronics
Difference between Atmega328 and Atmega328p
Amazon.com: ALMOCN 4Pcs MAX7219 8 Bit Digital Segment LED Display Tube 7-Segment Display Module for Arduino MCU/51/AVR/STM32/Raspberry Pi 4 Model B : Industrial & Scientific
Android Basics and User Interfaces
Can you use Arduino Digital I/O pins as GND and +5v? - Project Guidance - Arduino Forum