Classic Mega 2560 R3, ATmega16U2+ATmega2560-16AU, USB-B, Arduino-Compatible Board
Overview
The Classic Mega 2560 R3 is the faithful clone of the official Arduino Mega 2560 R3, using the same components as Italian-made boards:
- ATmega16U2 USB-Serial converter (not CH340G)
- ATmega2560-16AU main microcontroller (TQFP-100, same as Italian Arduino)
- USB Type-B connector
- Standard Arduino Mega R3 form factor and pinout
If you need the full power of the Mega 2560 (54 digital I/O, 16 analog inputs, 4 UARTs, 256 KB flash) but want the most original-Arduino-like experience — this is the right board.
Why “Classic” Over CH340G Variants?
Compared to the cheaper Mega 2560 PRO Embed which uses CH340G:
- Genuine ATmega16U2 USB chip (more reliable auto-reset, reflashable for HID)
- Standard Arduino Mega R3 footprint (fully shield-compatible — the PRO Embed is much smaller and NOT shield-compatible)
- USB Type-B (more durable than Micro-USB for permanent installs)
- Identical electrical behavior to official Arduino Mega — works with every shield ever made for the Mega
Practical bottom line: if you have Mega-compatible shields (CAN bus shield, ethernet shield, motor shield, sensor shield, RAMPS 3D printer shield, etc.) and want to use them — buy this, not the PRO Embed.
When to Choose the Mega Over an UNO
| Feature | UNO R3 | Mega 2560 R3 |
|---|---|---|
| Digital I/O | 14 | 54 |
| PWM outputs | 6 | 15 |
| Analog inputs | 6 | 16 |
| Hardware UARTs | 1 | 4 |
| Flash | 32 KB | 256 KB (8×) |
| SRAM | 2 KB | 8 KB (4×) |
| Price | Cheaper | More expensive |
Choose the Mega when you need:
- More than 14 digital pins (e.g. driving multiple stepper motors, large LED arrays, mass-flash chips)
- Multiple UART devices (GPS + GSM + Bluetooth + Serial debug — all hardware UART)
- Large sketches (libraries like SD card, full TFT display, complex state machines easily exceed 32 KB)
- Compatibility with Mega-only shields (RAMPS, MegaShield, etc.)
Programming
Standard Arduino workflow:
- Install Arduino IDE
- Connect via USB Type-B
- Tools → Board → Arduino Mega or Mega 2560
- Tools → Processor → ATmega2560 (Mega 2560)
- Select serial port and upload
No driver installation needed on modern OS — ATmega16U2 enumerates as a standard USB CDC device.
Common Uses
- 3D printer mainboards (with RAMPS 1.4 / 1.6 shield — the de facto standard for DIY 3D printers)
- Multi-channel data loggers (16 ADC channels)
- Stage lighting controllers (54 PWM-capable outputs)
- Industrial sensor hubs (multiple I²C / SPI / UART devices)
- CNC controllers (GRBL fork on Mega: more axes than UNO supports)
- DMX-512 lighting (one of the 4 UARTs runs DMX, the others handle UI / sensors)
Related Products
- Mega 2560 PRO Embed — same MCU, much smaller, NOT shield-compatible
- Mega 2560 PRO Mini — even smaller, no onboard USB
- Classic UNO R3 — smaller sibling
- MEGA+WiFi R3 — same MCU + onboard ESP8266 WiFi
Where to Buy in 2026
RobotDyn discontinued. Look for these in product photos:
- Square IC labeled ATmega16U2 near the USB Type-B connector
- Large IC labeled ATmega2560-16AU in the middle (TQFP-100 package)
- USB Type-B connector (square-ish, not Micro-USB)
Many “Mega 2560” listings actually ship with CH340G — that’s fine for most purposes but not strictly “classic”. Specify ATmega16U2 in your search to get the genuine clone.
Documentation
- Schematic (PDF) — pinout/dimensions identical to ATmega16U2 variant