The Due is a microcontroller board based on the Atmel SAM3X8E ARM Cortex-M3 CPU. The Due Arduino AT91SAM3X8E ARM Cortex-M3 Board is the first Arduino board based on a 32-bit ARM core microcontroller. It has 54 digital input / output pins (of which 12 can be used as PWM outputs), 12 analog inputs, 4 UARTs (hardware serial ports), a 84 MHz clock, an USB OTG capable connection, 2 DAC (digital to analog), 2 TWI, a power jack, an SPI header, a JTAG header, a reset button and an erase button.
The board contains everything needed to support the microcontroller; simply connect it to a computer with a micro-USB cable or power it with an AC-to-DC adapter or battery to get started. The Due is compatible with all Arduino shields that work at 3.3V and are compliant with the 1.0 Arduino pinout.
The SAM3X has 512KB (2 blocks of 256KB) of flash memory for storing code. The bootloader is pre-burned in a factory from Atmel and is stored in a dedicated ROM memory. The available SRAM is 96KB in two contiguous banks of 64KB and 32KB. All the available memory (Flash, RAM, and ROM) can be accessed directly as a flat addressing space.
It is possible to erase the Flash memory of the SAM3X with the onboard erase button. This will remove the currently loaded sketch from the MCU. To erase, press and hold the Erase button for a few seconds while the board is powered.
Due follows the 1.0 pinout:
TWI: SDA and SCL pins that are near to the AREF pin.
The IOREF pin which allows an attached shield with the proper configuration to adapt to the voltage provided by the board. This enables shield compatibility with a 3.3V board like the Due and AVR-based boards which operate at 5V.
An unconnected pin, reserved for future use
Connections / Interfaces
Digital I / O pins: 54
With PWM: 12