Intro

To work with a Forth system you need some kind of a console. A text terminal with RS-232 port has been used for this purpose in the past, today PCs have software to emulate terminals but do not have any RS-232 interface. But there are usually USB interfaces instead. The USB-CDC appears as a traditional RS-232 port in your operating system (Linux /dev/ttyACMx, Windoze COMx). No need to bother with baud rates, handshaking, parity and other awkward things.

USB-CDC Words (API)

cdc-emit   ( c -- ) Emit one character
cdc-key    ( -- c ) Receive one character
cdc-emit?  ( -- ? ) Ready to send a character
cdc-key?   ( -- ? ) Is there a key press ?

uart       ( -- )   redirect console to serial interface (UART)
cdc        ( -- )   redirect console to USB-CDC

For console redirection see terminalhooks.s.

Default console is UART, but if you press button SW2 on reset, the console is redirected to the USB-CDC device, see mecrisp.s. Default console for the dongle is USB-CDC.