This is the first part in a new side series to implement a TTL UART from scratch. I've changed my mind several times on adding a serial port to my homebrew cpu but I'd already given it quite a lot of thought. I figure it would be useful to build one even if I don't use it for the final build.
In this video I build a simple transmit circuit, it constantly sends a single character (Or the output of a counter), not hugely useful in it's own right but a good foundation to build on.
For test and demonstration I use an FTDI usb to UART cable, you could just as easily connect it to a Raspberry PI, an Arduino or a regular serial port (with a level shifter).
