(r7) TerminalIO < MecrispCube

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---+ Intro

To work with a Forth system you need some kind of a [[https://en.wikipedia.org/wiki/System_console][console]]. A text [[https://en.wikipedia.org/wiki/Computer_terminal#Text_terminals][terminal]] with [[https://en.wikipedia.org/wiki/RS-232][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 [[https://en.wikipedia.org/wiki/USB_communications_device_class][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.
 

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---+ Terminal-IO

Default console is USB-CDC, but if you press button SW2 on reset, the console is redirected to the UART device, see [[https://github.com/spyren/Mecrisp-Cube/blob/master/Forth/cube/mecrisp.s][mecrisp.s]]. If you press button SW1 on reset, the console is redirected to the Bluetooth LE Cable Replacement Service.
<pre>
emit? 	     ( -- Flag ) 	Ready to send a character?
key? 	     ( -- Flag ) 	Checks if a key is waiting
key 	     ( -- Char ) 	Waits for and fetches the pressed key
emit 	     ( Char -- ) 	Emits a character

hook-emit?   ( -- a-addr ) 	Hooks for redirecting terminal IO on the fly
hook-key?
hook-key
hook-emit

uart         ( -- )   redirect console to serial interface (UART)
cdc          ( -- )   redirect console to USB-CDC
crs          ( -- )   redirect console to BLE CRS
</pre>

<pre>
: ascii ( -- ) 
  127 32 do 
    i emit 
  loop 
;

: crs-ascii ( -- ) 
  127 32 do 
    i crs-emit 
  loop 
  10 crs-emit / LF
;
</pre>

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---+ USB-CDC Serial Communcation (API)

<pre>
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 ?
</pre>

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---+ UART Serial Communcation (API)

<pre>
serial-emit  ( c -- ) Emit one character
serial-key   ( -- c ) Receive one character
serial-emit? ( -- ? ) Ready to send a character
serial-key?  ( -- ? ) Is there a key press ?

baudrate     ( u -- ) set baud rate (e.g. 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, <b>115200</b>)
paritybit    ( u -- ) set parity bit <b>0 none</b>, 1 odd, 2 even, 3 mark, 4 space
wordlength   ( u -- ) set word length 7, <b>8</b>, 9 (including parity)
stopbits     ( u -- ) set stop bits <b>0 1 bit</b>, 1 1.5 bit, 2 2 bit
</pre>

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---+ BLE Cable Replacement Serial Communcation (API)

<pre>
crs-emit   ( c -- ) Emit one character
crs-key    ( -- c ) Receive one character
crs-emit?  ( -- ? ) Ready to send a character
crs-key?   ( -- ? ) Is there a key press ?
</pre>

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-- %USERSIG{PeterSchmid - 2020-04-20}%

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Topic revision: r7 - 2020-05-19 - PeterSchmid