I had a PREN student showing up into my office. He wanted to choose a microcontroller for that project. One requirement put on the table was “it needs USB”. Well, I asked why USB is required. I was not surprised by the answer: “to use USB instead of RS-232”. Wow. So what he really wanted was USB CDC (Communication Device Class). Yep. Most notebooks today have no serial COM port (see “Processor Expert Configurations“). But because “USB is serial” does not mean “USB CDC is simple”. Nope. USB is not simple. But it can be with Processor Expert.

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