Arduino-Cheatsheet

• It includes the basic syntax and built in functions for Arduino programmers

1. Sketch
2. Control-Structures
3. Operators
4. Variables-Arrays-and-Data-Types
5. Built-in-Functions
6. Libraries

Sketch

• Structure of the program

void setup(){
	//Runs only once and initiates the variables
}
Void loop{
	// Runs repeatedly and controls the board
}

• Functions

<return type> <name>(<params>) { ... } //syntax
int sum(int x,int y) {return x+y;} //example
//Return types
return x; // x must match return type
return; // For void return type

Control-Structures

//Conditional statement
if<condition>{ <statement> }else{ <statement> }

//Loops
while (<condiiton) { <statement> }

do{ <statement> }(<condiiton)// condition is tested at the end of loop 
for (initialization expression; condition for expression; update expression){    
	// body of the loop
}

//Loop control statement
break; // Exit a loop immediately
continue; // Go to next iteration

switch(var){
 case 1:
 <statement>
 break;
 case 2:
 <statement>
 break;
 default:
 <statement>
}

Operators

• Arithmetic

= //assignment
+ //add
- //subtract
* //multiply 
/ //divide
% //modulo

• Comparison

== //equal to
!= //not equal to
<  //less than 
>  //greater than
<= //less than or equal to
>= //greater than or equal to

• Boolean

&& // and
|| // or
!  // not

• Bitwise

&   //bitwise and 
|   //bitwise or
^   //bitwise xor 
~   //bitwise not
<<  //shift left 
>>  //shift right

• Compound

++ //increment
-- //decrement
+= //compound addition
-= //compound subtraction
*= //compound multiplication
/= //compound division
&= //compound bitwise and
|= //compound bitwise or

• Pointer access

& //reference: get a pointer
* //dereference: follow a pointer

sizeof() //unary operator used to compute the size of its operand (i.e) returns the amount of memory allocated

Variables, Arrays, and Data Types

• Numeric Constant

HIGH | LOW
INPUT | OUTPUT
156        // decimal
0b00110011 // binary
0267       // octal
0xC8       // hexadecimal
10U        // force unsigned
10L        // force long
10UL       // force unsigned long
10.0       // force floating point
10.2e6     // 10.2*10^6 = 1230000

• Data types

bool          // true or false
char          // -128 to 127, 's','@'
unsigned char // 0 to 255
byte          // 0 to 255
int           // -32768 to 32767
unsigned int  // 0 to 65535
word          // 0 to 65535
long          // -2147483648 to 2147483647
unsigned long // 0 to 4294967295
float         // -3.4028e+38 to 3.4028e+38
double        // -3.4028e+38 to 3.4028e+38
void          // no return value

• Array

int a[]={10,20,30};
int a[5]={1,2,3,4,5};
int a[5];

• Strings

char a[6] = {'H','e','l','l','o','\0'};
char a[6] = {'H','e','l','l','o'};
char a[6] = {"Hello"};
char a[] = {"Hello"};

• Qualifiers

static   // preserves the value even when they are out of their scope
volatile // in RAM (nice for ISR)--> to tell the compiler, that the value may change at any time.
const    //read-only
PROGMEM  //in flash memory

Built-in Functions

• Digital I/O

//Digital I/O pins: 0-13 
 pinMode(pin,[INPUT, OUTPUT, INPUT_PULLUP])
 int digitalRead(pin)
 digitalWrite(pin, [HIGH, LOW])

• Analog I/O

//Analog I/O pins: A0-A5
pinMode(pin,[INPUT, OUTPUT, INPUT_PULLUP])
int analogRead(pin)
analogWrite(pin, value) // PWM Out pins: 3 5 6 9 10 11
analogReference([DEFAULT, INTERNAL, EXTERNAL])

• Advanced I/O

tone(pin, freq_Hz)
tone(pin, freq_Hz, duration_ms)
noTone(pin)
shiftOut(dataPin, clockPin,[MSBFIRST, LSBFIRST], value)
unsigned long pulseIn(pin,[HIGH, LOW])

• Time

unsigned long millis() // Overflows at 50 days
unsigned long micros() // Overflows at 70 minutes
delay(msec) 
delayMicroseconds(usec)

• Math

min(x, y)
max(x, y) 
abs(x)

sqrt(x) 
pow(base, exponent)

constrain(x, minval, maxval)
map(val, fromL, fromH, toL, toH)

// Trignometric functions
sin(rad) 
cos(rad) 
tan(rad)

• Random number

randomSeed(seed) // long or int
long random(max) // 0 to max-1
long random(min, max)

• Bits and Bytes

lowByte(x) 
highByte(x)
bitRead(x, bitn)
bitWrite(x, bitn, bit)
bitSet(x, bitn)
bitClear(x, bitn)
bit(bitn) // bitn: 0=LSB 7=MSB

• Type conversions

char(<value>) 
byte(<value>)
int(<value>)
word(<value>)
long(<value>) 
float(<value>)

• External Interrupts

attachInterrupt(interrupt, function,[LOW, CHANGE, RISING, FALLING])
detachInterrupt(interrupt)
interrupts()
noInterrupts()

Libraries

• Serial.

//communication with PC or via RX/TX
begin([300, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200]) 
end()
int available() // #bytes available
int read() // -1 if none available
int peek() // Read w/o removing
flush()
print(data)
println(data)
write(byte)
write(char * string)
write(byte * data, size)
SerialEvent() // Called if data is ready

• EEPROM.h

// Access non-volatile memory
byte read(addr)
write(addr, byte)
EEPROM[index] // Access as array

• Servo.h

// Control servo motors
attach(pin, [min_uS, max_uS])
write(angle)          // 0 to 180
writeMicroseconds(uS) // 1000-2000; 1500 is midpoint
int read()            // 0 to 180
bool attached()
detach()

• SoftwareSerial.h

//Communication on any pin
SoftwareSerial(rxPin, txPin)
begin(long speed) // Up to 115200
listen()          // Only 1 can listen
isListening()     // at a time.
read, peek, print, println, write // Equivalent to Serial library

• Wire.h

//I²C communication
begin()     // Join a master
begin(addr) // Join a slave @ addr
requestFrom(address, count)
beginTransmission(addr) // Step 1
send(byte)              // Step 2
send(char * string)
send(byte * data, size)
endTransmission()       // Step 3
int available()         // Number of bytes available
byte receive()          // Return next byte
onReceive(handler)
onRequest(handler)