Electronic – arduino – What are the advantages of having USB part of the microcontroller (as the Leonardo does)


The new(ish) Arduino Leonardo has an ATmega32u4 microcontroller which is different from the Uno. This controller has built in USB functionality and it can interface with a PC as a HID which is different than any of the other Arduino boards.

What are the other advantages to using the ATmega32u4 chip instead of the ATmega328 which requited a USB-UART chip to program and had limited USB capabilities?

Best Answer

Speed! You can send out up to 1000 frames of data per second of data to the 32u4 using it's virtual serial port. The older boards with their FTDI chip and UART bridge are limited to around 38 kbaud before signal reliability problems start to set in.

You can also represent more devices than just 'com port' -- for instance emulating a keyboard and a mouse. If you get fancy and use a new firmware like LUFA you can appear to be many more types of devices.