This is an attempted hal implementation for the sam3x8e microcontroller used in Arduino Due in accordance with embedded-hal traits.
Very useful (necessary, even) in understanding this library is the Atmel/Microchip Datasheet for the SAM3X chips. The latest one at the time of writing was found here: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-11057-32-bit-Cortex-M3-Microcontroller-SAM3X-SAM3A_Datasheet.pdf
This implementation strives to do something useful over being perfect, as the "unproven" hal interfaces can't express the full set of capabilities available on SAM3X