Still, the main feature of the ATmega8U2/16U2/32U2 MCU's is the USB 2.0 engine. It is the basis for the Leonardo and
Sparkfun Pro Micro boards. There is an ADC section, and two full 8-bit I/O ports. These devices make it possible to have
USB enabled applications with a single MCU.
Power Supply vs. Maximum Frequency
The calculator below provides a way to find the maximum operating frequency for any valid power supply voltage (2.7 to 5.5). Enter the power
supply voltage and click "Calculate Max Frequency" to find the ATmega32U4's specified maximum clock speed at your Vcc.
Maximum Frequency Calculator for ATmega16U4/32U4
|I/O Pins ||22|
|ADC Channels ||0|
|RT Counter (w/osc)||0|
|Timers (8-bit) ||1|
|Timers (16-bit) ||1|
|PWM (8-bit) ||2|
|PWM (16-bit) ||3|
|USB 2.0 Engine ||1|
|Price (1's) ||$5.46||$6.18|
|Power Consumption (approximate) ||5.5mA + (0.5/MHz)|
|Maximum I/O Current (per pin) ||40mA|
|Maximum I/O Current (all ports) ||100mA(low)/150mA(high)|
|Maximum I/O Current (total) ||200mA (PDIP)|
|Maximum I/O Current (total)||400mA (PDIP/QFP/MLF)|
Link to ATmega16U4/32U4 datasheet from Atmel's website.