The Atmega controllers used for the Arduino contain an onboard 6 channel analog-to-digital (A/D) converter with 10 bit resolution (0-1023). The main function of the analog pins is to read analog sensors, but analog pins also have all the functions of digital pins (pin 0 to pin 13).
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Digital Pins of Arduino
The digital pins on the Arduino can be configured as either inputs or outputs. These pins works on HIGH(5V) and LOW(0V) states but some of them also works as PWM pins (We will talk about PWM in upcoming posts). There are 20K pullup resistors built into the Atmega chip that can be accessed from software. We will discuss