Manejo de elementos de entrada y salida (pulsadores y leds)

How to read inputs on microcontrollers?

Working with microcontrollers may seem complicated at first, but it is essential to know how to read inputs to unlock their full potential. Reading inputs allows microcontrollers to respond to external signals, such as a button being pressed. Here I will show you how to connect a pushbutton and read its state with a microcontroller using programming. Here we go!

How to configure the pins as input and output?

The configuration of microcontroller pins is crucial in determining how they will interact with the outside world. Basically, you need to configure one pin to function as input, and another to function as output. So you will have one pin that will receive data (a button press) and another that will act accordingly (such as turning on an LED).

To do this, you must use the tris instruction in the microcontroller code. Here is an example:

// Set B0 as inputtris B0 = 1;
// Set B2 as outputtris B2 = 0;

How is the button state reading achieved?

Reading the button state involves detecting whether the button is being pressed or not, and acting accordingly. Here we use a simple conditional structure to check the state of the pin where the button is connected (B0), and turn the LED (B2) on or off as needed.

if (RB0 == 1) { // If the button is pressed portBbits.RB2 = 1; // Turn on the LED} else { // If the button is not pressed portBbits.RB2 = 0; // Turn off the LED}

How to optimize code with autocomplete?

Writing code can become tedious, but fortunately, many code editors come with autocomplete functions that can make your life easier. Using the with command, you can quickly access autocomplete options:

with (DeV) { // Access all bits within a specific port The B2 = ...;}

How to verify and debug the program?

Once you have written your code, the next step is to check for errors. This check is usually done by compiling the code with the microcontroller's programming software. Here are a couple of steps:

1. Save the program.
2. Compile the code to make sure there are no syntax errors.
3. If you find errors, correct them before downloading the program to the microcontroller.

When you run the program, you should notice that:

• The LED is off by default.
• You press the button, the LED turns on.
• You release the button, the LED turns off.

It is good practice to maintain consistency and check that everything works as planned.

---

With this guide, you have learned the basics of working with inputs and outputs on microcontrollers and how to implement simple logic to respond to external inputs. Continue to explore and develop your skills; in future lessons, we will explore how to work with more complicated sensors. See you in the next class!