Arduino Micro USB Microcontroller is a microcontroller board based on the ATmega32u4. It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a micro USB cable to get started. It has a form factor that enables it to be easily placed on a breadboard.
Arduino Micro USB Microcontroller can be powered via the micro USB connection or with an external power supply. The power source is selected automatically. External (non-USB) power can come either from a DC power supply or battery. Leads from a battery or DC power supply can be connected to the Gnd and Vin pins. The ATmega32u4 has 32 KB. It also has 2.5 KB of SRAM and 1 KB of EEPROM.
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