The LilyPad Arduino USB is a microcontroller board based on the ATmega32u4. It has 9 digital input/output pins (of which 4 can be used as PWM outputs and 4 as analog inputs), an 8 MHz resonator, a micro USB connection, a JST connector for a 3.7V LiPo battery, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a battery to get started.
The LilyPad Arduino USB differs from previous LilyPad boards in that the ATmega32u4 has built-in USB communication, eliminating the need for a separate USB-to-serial adapter. This allows the LilyPad Arduino USB to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.
Summary
| Microcontroller | ATmega32u4 |
| Operating Voltage | 3.3V |
| Input Voltage | 3.8V to 5V via USB / Lipo battery / external supply |
| Digital I/O Pins | 9 |
| PWM Channels | 4 |
| Analog Input Channels | 4 |
| DC Current per I/O Pin | 40 mA |
| Flash Memory | 32 KB (ATmega32u4) of which 4 KB used by bootloader |
| SRAM | 2.5 KB (ATmega32u4) |
| EEPROM | 1 KB (ATmega32u4) |
| Clock Speed | 8 MHz |
