This feature isn’t exclusive to the Leonoardo, as [Michael] explains in a build he sent in – the lowly Arduino Uno can also serve as a USB HID keyboard with just a firmware update.

[Damian] still needed input, output, and the ROM which made ... The 16u2 is normally used as the Arduino Uno’s USB interface. The only external hardware needed is a single 120 ohm resistor.

Then, an Arduino ... analog input pins) now have a special functionality as OPAMP pins, capable of outputting the same voltage or increasing the voltage connected to it. The Uno R4 WiFi Has ...

To achieve this, the USB bus is ... to the ESP32. “Uno R4 WiFi includes an error-catching mechanism that detects run-time crashes and provides detailed explanations and hints about the code line ...