## Links
- [Atmega 32U4 datasheet](https://ww1.microchip.com/downloads/en/devicedoc/atmel-7766-8-bit-avr-atmega16u4-32u4_datasheet.pdf)
- [Atmel SAM3X/3A datasheet](https://copperhilltech.com/content/Atmel-SAM3X-Datasheet.pdf)
- [Atmega 32U4 AVR035: Efficient C Coding for AVR](https://ww1.microchip.com/downloads/en/Appnotes/doc1497.pdf)