3.1 Introduction to Arduino - programming
APSC 160 – part 2
2
Arduino Programming
+Arduino platforms are designed to use the C++ programming
language
+C++ is a superset of C
+ So we can use C to program Arduinos
+ All we have learned so far: control statements, loops, functions, arrays, etc.
+In addition, we will learn about:
+ The structure that Arduino programs use (has to do with Arduino being an
embedded systems platform)
+ Some Arduino functions
3
Arduino Programming
+In this slide set, we will learn about:
• setup()
• loop()
Used for initialization and flow
control of the program
• pinMode()
Used to specify the direction of a
pin (input, output)
• digitalRead()
• digitalWrite()
Used IO (or I/O): reading from
a digital input and writing into a
digital output device
4
Arduino program structure
+An Arduino program does not have a main() function. This
may seem odd as we learned in part 1 that every C program
must have a main() function.
+main() still exists but it’s hidden
+Two functions are used instead in every Arduino program:
+setup()
+Loop()
+Sometimes an Arduino program is called a sketch.
5
Typical Arduino program framework
+The starting skeleton (structure) of an Arduino program is:
// variable declarations, compiler directives
void setup() {
// code here
}
void loop()
{
// code here
}
6
setup()
+The setup() function is called exactly once when the program starts.
void setup() {
// code here
+We include here
anything that we want executed once when the
}
program starts, normally to set things up.
+ Takes no parameter, returns nothing
+setup() reference page:
+ https://www.arduino.cc/reference/en/language/structure/sketch/setup/
7
loop()
+After the setup() function is executed – exactly once – the
loop() function is called (executed) repeatedly. The code in
the loop() function will loop consecutively:
void loop()
{
// code here
}
+The loop() function creates a forever (infinite) loop
mechanism (also called superloop)
+Takes no parameter, returns nothing
+loop() reference page:
+https://www.arduino.cc/reference/en/language/structure/sketch/loop/
8
Superloop
+Arduino (embedded) programs always include some tasks that we want to
be performed repeatedly.
+A repetitive structure, usually called a superloop, includes all tasks that
need to be executed repeatedly.
+This approach is very common in embedded programming (including
Arduinos)
Arduino implementation
void loop()
{
General purpose C code
/* within some function
while(true) {
/* your code to implement
repetitive tasks here */
/* your code to implement
repetitive tasks here */
}
}
9
Summary
+Arduino programs are C (or C++) programs with a specific (modified)
structure
+ There is no main() function. There are two primary functions in all Arduino
programs: setup() and loop()
+ Setup() is executed exactly once and includes all initialization instructions.
+ Loop() is a function that acts as a superloop (infinite loop) for all programs.
This function will be executed repeatedly as long as the Arduino is powered
up, immediately after the setup() function is executed.
+ Other than the above, every Arduino program is a C (C++) program. You can
add as much functionality as needed.