All three pins are capable of PWM output (Arduino Reference). This allows you to simulate analog results (like dimming an LED or controlling motor speed) using digital signals.

In many standard LiquidCrystal setups, pins 11 and 10 are the default choices for the Enable (E) and Register Select (RS) connections.

Pins 9 and 10 are hardware-linked to Timer 1 , a 16-bit timer that provides higher resolution for PWM compared to other pins. 🛠️ Hardware Specifications Pin Number Primary Function Special Feature Linked Hardware 9 Digital I/O 10 Digital I/O 8-bit PWM / SPI (SS) 11 Digital I/O 8-bit PWM / SPI (MOSI) ⚠️ Important Usage Notes

These three pins (9, 10, and 11) are frequently used as the address lines for 4051/4052 analog multiplexers to expand the number of sensors you can read.

On an Arduino Uno, pins 9, 10, and 11 are part of a specific group of pins with dual-purpose functionality:

MISO (Master In Slave Out) — often paired with 10 and 11