KIM-1 TTY I/O, no echo, non-blocking, deaf

A page on suppressing the KIM-1 echo of TTY input, read non-blocking and make the TTY input deaf.

Problems with the KIM-1 TTY character input

The KIM-1 hardware is hardware echoing incoming serial characters to the output, no echo in software involved, so you cannot influence what appears on screen. Very annoying!
The KIM-1 GETCH routine is blocking, no way to check for a character coming in, like a Break. waiting.
Also quite annoying if porting other software to the KIM-1 or you want the program interruptable.
While a program is running something CPU intensive and you type something the program is not really waiting for, the characters appear on screen. Because the KIM-1 does hardware echoing of TTY input, this is unavoidable it seems

Here I present solutions for these problems in software, made possible by the genius hardware design of the KIM-1 TTY I/O.
You can have serial input wihout echo, non-blocking and even make the TTY input deaf for unwanted input.

Are they perfect? Maybe not, it is still bitbanging the incoming serial signal. It can miss the correct starting point for the incoming character bit stream.
If you want a perfect solution, you will need interrupt driven ringbuffered serial I/O with a dedicated IC like the 6850, 6511 etc.
Without this extra hardware you can achieve acceptable results with these routines.