Arduino Project Handbook

Appendix B: Arduino Pin Reference

Without going into too much detail, this appendix gives you a reference to the pins on the Arduino Uno, their technical names, and their functions. The pins are explained in more detail in the projects in which they’re used, so the information here will probably make more sense once you’ve built a few projects.

ARDUINO PIN	FUNCTION AND LABEL	ADDITIONAL FUNCTION
0	RX—Used to receive TTL serial data
1	TX—Used to transmit TTL serial data
2	External interrupt
3	External interrupt	Pulse width modulation
4	XCK/TO—External Clock Input/Output (Timer/Counter 0)
5	T1 (Timer/Counter 1)	Pulse width modulation
6	AIN0—Analog comparator positive input	Pulse width modulation
7	AIN1—Analog comparator ...