Beyond the Blinky LED: Building a Command Interpreter for Microcontrollers

The blinky LED project is simple: you connect an LED to a digital output pin and add a resistor in line with either the positive or negative terminal. By adjusting the resistor, allows you to control the LED’s brightness based on its color and voltage needs. This beginner project gives you a hands-on understanding of how code can control real-world objects.

You completed this project and are now looking for the next one. The next step is to build a command interpreter.

A command interpreter allows you to type commands into your microcontroller and get a response in real-time—just like the terminal on your computer. With this project, you’ll build a simple command interpreter that lets you control your microcontroller interactively, a skill commonly used in embedded systems for testing and debugging.

What you will learn

The reason this is an excellent next project is because you will need to learn and understand:

• Serial Communication: Transmitting data between your microcontroller and computer.
• Setting Baud Rate: Defining the speed for data transmission.
• Line Termination: Ensuring that each command the microcontroller understands you type.
• Working with Serial Emulators: Testing commands directly from your computer.
• String Parsing and Comparison: Break down commands and check them against defined instructions.
• State Machine Programming: Creating a structured way for your program to handle different commands logically.

Recommended commands

Set a few commands in your microcontroller command interpreter.

• help - Lists available commands. Example: help displays all commands with short descriptions.
• echo - Repeats the text you type. Example: echo Hello responds with “Hello.”
• analog-read <ch #> - Reads an analog value from a specified channel. Example: analog-read 1 gives a reading from channel 1.
• digital-on <ch #> - Turns a digital output ON. Example: digital-on 2 turns on channel 2.
• digital-off <ch #> - Turns a digital output OFF. Example: digital-off 2 turns off channel 2.

Wrap up

This project is a solid introduction to building embedded command interpreters. As you set up each command, you’ll get a feel for reading analog inputs, controlling digital outputs, and managing serial communication. Even in more advanced systems, serial communication is a reliable and efficient method for testing, debugging, and even real-time control in industrial applications.

With each command you add, you’re expanding your microcontroller’s capabilities. Dive in, experiment, and enjoy the process!