C Programming for Arduino: Building your own electronic devices is fascinating fun and this book helps you enter the world of autonomous but connected devices. After an introduction to the Arduino board, you'll end up learning some skills to surprise yourself.

The first question is, what is a program?

A program is text that you write using a programming language that contains behaviors that you need a processor to acquire. It basically creates a way of handling inputs and producing outputs according to these behaviors.

According to Wikipedia (http://en.wikipedia.org/wiki/Computer_programming):

Of course, this definition is very simple and it also applies to microcontrollers, as we already know that the latter are basically a type of computers.

Designing a program is the fact you have to think about first, before you begin coding it. It generally involves writing, drawing, and making schematics of all the actions you want your processor to make for you. Sometimes, it also implies to write what we call pseudocode. I hope you remember that this is what we created in the previous chapter when we wanted...

Dennis Ritchie http://en.wikipedia.org/wiki/Dennis_Ritchie) at Bell Labs developed the C programming language from 1969 to 1973. It is often defined as a general-purpose programming language and is indeed one of the most used languages of all times. It had been used initially to design the Unix operating system (http://en.wikipedia.org/wiki/Unix) that had numerous requirements, especially high performance.

It has influenced a lot of very well known and used languages such as C++, Objective-C, Java, JavaScript, Perl, PHP, and many others.

C is to both imperative and structured. It is very appropriate for both 8-bit and 64-bit processors, for systems having not only several bytes of memory but also terabytes too, and also for huge projects involving huge teams, to the smallest of projects with a single developer.

Yes, we are going to learn a language that will open your mind to global and universal programming concepts!

A programming library is a collection of resources that are available for use by programs.

They can include different types of things, such as the following:

I like to say that libraries provide a behavior encapsulation; you don't have to know how the behavior is made for using it but you just use it.

Libraries can be very specific, or can have a global purpose.

For instance, if you intend to design firmware that connects the Arduino to the Internet in order to grab some information from a mail server, and react by making an LED matrix blink in one way or another according to the content of the mail server's response, you have the following two solutions:

Even if we like to code things, we are happier if we can focus on the global purpose of our designs, aren't we?

In that case, we'll try...

We are not here together to understand the entire details of code compilation. But I want to give you a global explanation that will help you to understand better how it works under the hood. It will also help you to understand how to debug your source code and why something wouldn't work in any random case.

Let's begin by a flowchart showing the entire process.

From the source code to the binary executable code

The following steps are executed to take the code from the source to the executable production stage:

The Arduino board itself can communicate easily using basic protocols for serial communication.

Basically, serial communication is the process of sending data elements over a channel, often named a bus. Usually, data elements are bytes, but it all depends on the implementation of the serial communication.

In serial communication, data is sent sequentially, one after the previous one. This is the opposite of parallel communication, where data are sent over more than one channel, all at the same time.

Imagine that you have followed carefully the Blink250ms project, everything is wired correctly, you double-checked that, and the code seems okay too, but it doesn't work.

Our LED isn't blinking at all. How to be sure that the loop() structure of your code is correctly running? We'll modify the code a bit in order to trace its steps.

In this chapter, we learned about programming using C language. We also learned how to use the serial monitoring feature of our Arduino IDE in order to know a bit more about what is happening in real time in our Arduino processor using traces.

I spoke about serial communication because it is very useful and is also used in many real-life projects in which you need a computer and an Arduino board to communicate among themselves. It can also be used between two Arduino boards or between Arduino boards and other circuits.

In the next chapter, we'll enter C code by using the serial monitoring window in order to make things a bit less abstract.