Though [David] could have easily used USB OTG for this project, many microcontrollers don’t have the USB-to-TTL capabilities of his Arduino ... waveform. The 8-bit data chunks he sent ...

[Ralph] created a software library and a small circuit that enables half duplex UART using only one pin. With the above circuit, and a 62 byte Arduino compatible library, you can add UART to the ...

The need for a second UART port ( and one that is not shared with USB) on the Arduino Uno is so great that the “SoftwareSerial” library in included in the Arduino IDE. It emulates additional ...