Homemade Arduino Part 1: Programming an Atmega328 on a Breadboard (Shallow Thoughts)
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atmega - Can I use ATmega328 TX/RX pins to drive an R2R network and still use the serial port to program the MCU? - Electrical Engineering Stack Exchange
Serial Communications - Arduino Cookbook, 3rd Edition [Book]
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Pin Configuration and IO Multiplexing : Arduino / ATmega328p - Arnab Kumar Das
AVR Programmer Serial Port – Circuit Diagram – Embedded Electronics Blog
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LAFVIN Nano V3.0, Nano Board ATmega328P 5V 16M Micro-Controller Board Compatible with Arduino IDE (Nano x 3 with USB Cable)
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Smiley's Workshop 40: Digital I/O — Part 2 | Nuts & Volts Magazine
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