A single prime number benchmark sketch.

forked from : https://github.com/RalphBacon/LGT8F328P-Arduino-Clone-Chip-ATMega328P

Modifications :

• runs out of the box on LGT8Fx boards @ 16MHz using default Arduino Nano core.
• runs out of the box on LGT8Fx boards @ 32MHz and 16MHz using Larduino_HSP core.
• runs out of the box on old Arduino boards that does not have GUID
• runs out of the box on non AVR boards

Calculate 10,000 prime numbers :

• ATmega328p @ 16MHz : 121 seconds (Duemilanove made in Italy)

• ATmega328p @ 16MHz : 121 seconds (Uno + CH340 made in China)

• ATmega32u4 @ 16MHz : 120 seconds (Leonardo made in Italy)

• ATmega32u4 @ 16MHz : 120 seconds (Leonardo Micro made in China)

• ATmega328p @ 8MHz : 242 seconds (Mini pro 3.3V made in China)

• LGT8F328p @ 16MHz : 118 seconds using default Arduino Nano stuff (old bootloader)

• LGT8F328p @ 16MHz : 118 seconds using Larduino_HSP

• LGT8F328p @ 32MHz : 59 seconds using Larduino_HSP

• STM32F103 @ 72MHz : 3 seconds using Arduino_Core_STM32 ("Blue Pill" made in China)