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Arduino Mega 2560 R3

ATmega2560 with 54 digital I/O, 16 analog inputs, 4 hardware UARTs, and 256 KB flash. The board you reach for when Uno runs out of pins or memory.

In stock CC-BY-SA-4.0 4 files · 3.2 MB

Specs

Spec Value
MCU ATmega2560
Clock 16 MHz
Operating voltage 5 V
Input voltage (DC jack) 7–12 V
Digital I/O 54 (15 PWM)
Analog inputs 16
UARTs 4 (Serial, Serial1–3)
Flash / SRAM / EEPROM 256 KB / 8 KB / 4 KB
USB Type-B

Pinout summary

Pin block Function
D0–D53 General-purpose digital
D2–D13, D44–D46 PWM (15 pins)
D18 (TX1) / D19 (RX1) Serial1
D16 (TX2) / D17 (RX2) Serial2
D14 (TX3) / D15 (RX3) Serial3
D20 (SDA) / D21 (SCL) I²C
D50–D53 SPI (MISO, MOSI, SCK, SS)
A0–A15 10-bit ADC

When to pick Mega vs Uno

  • More than 14 GPIO needed (LED matrix, large keypad, many sensors)
  • More than one hardware UART (GPS + Bluetooth + debug)
  • Sketches over 30 KB (32 KB Uno limit)

Schematic

Open schematic (PDF)

Last updated: 2026-05-13 · Source on GitHub