If you drive a pin that’s already an output, for example, you could do real harm to the board. Because all the pins are shared, you have the same problem with the Arduino pins, too.

The whole thing worked because of all the generous people who have written Arduino code, and also code to adapt the basic Arduino stuff to work with alternative chips from the Microchip was Atmel) AVR ...

In the Leonardo, an op-amp between the ATmega pin and the led means that loading is minimal and the pin can easily be used as an Arduino input. This buffer is missing on the Micro, which means even ...

Not long after [CulinarilySpeaking] got into the Arduino game, he began to want more IO pins and a larger program space for more ambitious projects. This, of course, led him down the path towards t… ...