- The ATmel MCU ATMEGA16U2 MEGA 2560 R3 Improved Version CH340G Board is a micro-controller board base on the ATmega2560. It has a USB host interface to connect with Android based phones, base on the MAX3421e IC.
It has 54 digital input/output pins (of which 15 can be used as PWM outputs); 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator; a USB connection, a power jack, an ICSP header, and a reset button. The MEGA ADK is base on the Mega 2560. Similar to the Mega 2560 and Uno, it features an ATmega8U2 program as a USB-to-serial converter. Revision 3 of the Mega ADK board has a resistor pulling the 8U2 HWB line to ground, making it easier to put into DFU(Device Firmware Upgrade) mode.
The board has the following new features:
- 1.0 pin-out: added SDA and SCL pins that are near to the AREF pin and two other new pins placed near to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board. In the future, shields will be compatible both with the board that uses the AVR, which operate with 5V and with the Arduino Due that operates with 3.3V. The second one is a not connected pin, that is reserved for future purposes.
- Stronger RESET circuit.
The Mega Arduino R3 Android Accessory Development Kit (ADK) can be power via the USB connection or with an external power supply. The power source is select automatically. External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board’s power jack.
Leads from a battery can be inserted in the GND and Vin pin headers of the POWER connector. Because the Mega R3 Android Accessory Development Kit (ADK) is a USB Host, the phone will attempt to draw power from it when it needs to charge. When the ADK is power over USB, 500mA total is available for the phone and board.