Arduino Cheatsheet

1 minute read


Duration timers, starts at 0 at boot.

uint32_t ms = millis();
uint32_t us = micros();


delay(uint32_t ms);
delayMicroseconds(uint32_t us);


Boards may have more than one serial channel, Serial is the primary; then Serial1, Serial2, etc.

Enable a serial channel with baud rate:

Serial.begin(int baud);
if (Serial) // = true when Serial is ready

Receiving bytes:

int numBytes = Serial.avaliable();
int byte =; // returns -1 if no byte avaliable
size_t numBytesRead = Serial.readBytes(char* buffer, int len);

Writing bytes:

Serial.write(int byte);     // write a single byte
Serial.write(char* string); // write a \0 term string
Serial.write(char* buffer, int len);

Print writing:

Serial.print(int val);
Serial.print(int val, HEX); // BIN, OCT, DEC, HEX
Serial.print(float val);
Serial.print(float val, int decimalPlaces);

Close serial port:


Digital I/O

Setting pin modes

pinMode(int pin, OUTPUT);
pinMode(int pin, INPUT);
pinMode(int pin, INPUT_PULLUP);

Using digital pins:

digitalWrite(int pin, LOW);
digitalWrite(int pin, HIGH);
int val = digitalRead(int pin); // return is HIGH/LOW


Resolution capability depends on the board being used (Teensy 3.2 can be changed from 2 to 13 bits).

Default is 10-bits.

pinMode(int pin, INPUT);
analogReadResolution(int pin, int resolution);
uint16_t val = analogRead(int pin);


Resolution capability depends on the board being used (Teensy 3.2 can be changed from 2 to 16 bits).

Default is 10-bit PWM.

pinMode(int pin, OUTPUT);
analogWriteResolution(int pin, int resolution);
analogWrite(int pin, int val);

If your board has DAC support, the same code works.