ADDED support for STRING & INT arrays
ADDED support for Bitmap files

BackSpace [8] & Ctrl-C [3] now works from Serial term

NEW       [v] reset PRGM & VARS

BEEP      [v] duration * 50ms / 1..48 octave #2 to #5 / else frequency (49..4096)
TONE      [v] play a tone on speaker
NOTONE    [v] mute speaker
PLAYT5K   [v] PLAYS a T5K tune
PLAYT53   [v] PLAYS a T53 tune

LED       [v] LED 1,1 turn on 1st led // LED 3,0 turn off 3rd

RSEED     [v] does nothing ...
DELAY     [v] wait for x milliseconds

PRINT / ? [v] still have to distinguish ',' & ';'
OUT       [v] print a char of ascii code , can be redirected to FILEIODesc
CLS       [v] clear current screen (LCD_BUILTIN, later : VGA ....)
LOCATE    [v] Set text cursor position (x,y)
PSET      [v] set a pixel (since git:6266540)
PRESET    [v] clear a pixel (since git:6266540)
LINE      [v] draws a line (since git:6266540)
CIRCLE    [v] draws a circle (since git:6266540)
DRAWBMP   [v] draw a bitmap from storage

INPUT     [v] INPUT content into a variable (NUM or STR) -> can use FILEIODesc to select stream
INPUTSTR  [v] INPUT content into a variable (STR) -> can use FILEIODesc to select stream

REM / '   [v] make a line comment

FILES     [v] list storage content
CAT       [v] read a specific file (w/o interpret it)

DELETE    [v] erase a file from storage
DUMPSTS   [v] dump serial to SD file  // DUMPSTS "" -> read until timeout
WRITE     [ ]
WRITETEXT [ ]

LIST      [v] List content of PRGM memory [ need checkbreack() ]
RUN       [v] Run content of PRGM memory [ need checkbreack() ]
LOAD      [v] (does it starts by a 'NEW' statement ? // I think not // so lines could be merged)
SAVE      [v] Save content of PRGM memory // slow impl. .... // auto-adds '.BAS' if needed
CHAIN     [v] => NEW / LOAD / RUN a program

FOR       [ ] FOR / TO / [STEP] / NEXT
IF        [v] IF  THEN ...
GOTO      [v] Jump directly to a line
GOSUB     [v] Jump to line after saving current position
RETURN    [v] return to current position after GOSUB

END / STOP[v] STOPS execution of current program

--------------------------

RND(x)    [v] return int between 0 & x

CHR$(x)   [v] return ASCII char from x
STR$(x)   [v] return string representing number x
ASC(x)    [v] return ASCII code of 1st char of 'x' string
STRLEN()  [v] length of a String value
LEN()     [v] length of a String value

LEFT$()   [v] return left chars of a string
RIGHT$()  [v] return right chars of a string
MID$()    [v] return substring of a string
INSTR()   [v] return first occurence of a substring in a string


FREE()    [v] return ammount of free RAM in bytes (beware it's an int not a short)
MEM()     [v] return ammount of free RAM in kilobytes (cause it's a short @this time)

BTN()     [v] returns 0,1,2,4 => Cf pressed user btn(s)

INP()     [v] wait for a char from input // can use FILEIO-Desc
SNS()     [v] read for a char from input (0 if none) // can use FILEIO-Desc

SECS()    [v] seconds since MCU booted