EMBEDDED BASIC Feb 14, 2011
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Program:
  All program lines must start with a line number.
  It is customary to use increments of 10 in case you want to add some lines in-between afterwords.


Variables:
  Variable names must start with a letter, may contain letters and numbers, may be up to 8 characters long
  FOR..NEXT variables must be a single letter
  Variables are 32-bit signed integers


Registers:
   DIRA        Pin direction 0=INPUT; 1=OUTPUT - write-only
   OUTA        Pin outputs 0=LOW; 1=HIGH       - write-only
   INA         Pin inputs 0=LOW; 1=HIGH        - read-only
   CNT         System counter                  - read-only
   CTRA, CTRB  Counter mode                    - write-only
   FRQA, FRQB  Counter frequency               - write-only
   PHSA, PHSB  Counter phase                   - write-only
   VCFG, VSCL  Sets video generator            - write-only
   INKEY       Returns value of keypress       - read-only
   VARS        Address of variables            - read-only
   CHARS       Address of character bitmaps    - read-only


Pin I/O:
  INPUT, OUTPUT, HIGH, LOW, PIN

  For all commands that operate on hardware pins you can specify a range of pins by using MSB..LSB.
  For example to make pin 23 high use: HIGH 23
  To make pins 24 thru 26 high use: HIGH 24..26
  !!! NOTE if the MSB value is less than the LSB value, the bits will be reversed, this is the same as the spin language !!!


Operators (in order of precedence):
  Parenthesis ( )
  UNARY +, UNARY -, !, ABS, RND, PEEKB, PEEKW, PEEKL, PIN, ..  
  SHL, SHR, ROL, ROR, SAR, REV
  &
  |, ^
  *, /, //
  +, -
  =, <, >, <=, >=, <>
  NOT
  AND
  OR

   &, |, ^ are bitwise (AND,OR,XOR); "AND" and "OR" are logical AND and OR.
     4 | 1 = 5 ; 4 OR 1 = -1


Commands:
  BCOLOR       BCOLOR {expression}
               Sets the background color (see COLOR, FCOLOR)

  CLS          CLS
               Clears the screen

  COLOR        COLOR {expression}
               Sets both background and foreground colors with one value (see BCOLOR, FCOLOR)

  CONT         CONT {expression}
               Continue program after ESC is pressed

  DATA         DATA expression, expression, expression
               Define data to be read with READ (see READ, RESTORE)

  DEBUG        DEBUG
               Shows line #'s as program runs

  DISPLAY      DISPLAY 42 ' prints a "*"
               Prints ascii character. May use multiple paramters.
               Value 10 moves to next line and moves back to starting position (for multi line displays)

  DUMP         DUMP
               Shows program bytes, press a key to stop

  END          END
               Stops program and returns to command prompt

  FCOLOR       FCOLOR {expression}
               Sets the foreground color (see COLOR, BCOLOR)

  FOR/TO/STEP  FOR A = 1 TO 10 {STEP 1} (only single letter variable names)
               Creates a program loop

  GOSUB        GOSUB 1000
               Go to subroutine (see RETURN)

  GOTO         GOTO 1000
               Jumps to line 

  HIGH         HIGH 23
               HIGH 23..26
               Make pin(s) an output and high

  IF/THEN      IF A = B THEN GOTO 1000
               IF A <> B THEN c=1000:d=1000
               If the condition is true, execute commands following THEN

  INPUT        INPUT 23
               INPUT 23..26
               Make pin(s) an input

  LET          LET A=A*10
               LET A=PIN 27..24
               Assigns a value to a variable. (LET is optional)

  LIST         LIST
               LIST 1000
               Show program listing (Press a key to stop)

  LOAD         LOAD
               LOAD 1
               Retrieves program from EEPROM, if 64K eeprom can use LOAD [1-4]

  LOCATE       LOCATE 5, 10
               Sets print location

  LOW          LOW 23
               LOW 23..26
               Make pin(s) an output and low

  NEW          NEW
               Clears program and displays version info

  NEXT         NEXT A
               Adjusts value and loops back to FOR line

  NODEBUG      NODEBUG
               Does NOT show line #'s as it runs (see DEBUG)

  OUTPUT       OUTPUT 23
               OUTPUT 23..26
               Makes pin(S) an output

  PAUSE        PAUSE 1000
               Pauses for value milliseconds

  PIN          PIN 23,1
               PIN 27..24,15
               Sets pin output state. NOTE: DOES NOT SET PIN TO OUTPUT

  POKEB        POKEB a,100
               Changes a byte of program memory (RAM, not EEPROM)

  POKEW        POKEW a,1000
               Changes a word of program memory (RAM, not EEPROM)

  POKEL        POKEL a,100000
               Changes a long of program memory (RAM, not EEPROM)

  PRINT        PRINT
               PRINT a
               PRINT "The value is ";a
               Prints to the screen.

  READ         READ A,B,C
               Reads data from the DATA lines

  REM          REM This is a comment
               dirx = 1 ' set direction to 1
               Comment

  RESTORE      RESTORE
               RESTORE 1000
               Set line that READ will start reading data from

  RETURN       RETURN
               Return from subroutine

  RUN          RUN
               RUN 1000
               Runs program

  SAVE         SAVE
               SAVE 1
               SAVEs program to EEPROM, if 64K eeprom can use SAVE [1-4]


  NOTE:
    Single letter variable names are faster than multi-letter variable names

    FOR...NEXT is faster than GOTO
      GOTO needs to scan from the beginning to find the line # requested

    FOR does NOT have to be the first command on a line.
      10 CLS: FOR a=1 TO 10:PRINT a:NEXT a

    x..y returns (x + y*256 + 11141120) 11141120 = $AA0000 and is just a unique number which means (this is a .. result)
       x..y - 0..0 = x + y*256