evost / TinyBasicPlus

A C implementation of Tiny Basic, with a focus on support for Arduino

TinyBasic Plus

Full list of supported statements and functions

System

• BYE - exits Basic, soft reboot on Arduino
• END - stops execution from the program, also "STOP"
• MEM - displays memory usage statistics
• NEW - clears the current program
• RUN - executes the current program
• LIST - print out the current program

File IO/SD Card

• FILES - lists the files on the SD card
• LOAD filename.bas - loads a file from the SD card
• CHAIN filename.bas - equivalent of: new, load filename.bas, run
• SAVE filename.bas - saves the current program to the SD card, overwriting

IO, Documentation

• INPUT variable - let the user input an expression (number or variable name)
• PRINT expression - print out the expression, also "?"
• REM stuff - remark/comment, also "'"

Expressions, Math

• A=V, LET A=V - assign value to a variable
• +, -, *, / - Math
• <,<=,=,<>,!=,>=,> - Comparisons
• ABS( expression ) - returns the absolute value of the expression
• RSEED( v ) - sets the random seed to v
• RND( m ) - returns a random number from 0 to m-1

Control

• IF expression statement - perform statement if expression is true
• FOR variable = start TO end - start for block
• FOR variable = start TO end STEP value - start for block with step
• NEXT - end of for block
• GOTO linenumber - continue execution at this line number
• GOSUB linenumber - call a subroutine at this line number
• RETURN - return from a subroutine

Pin IO

• DELAY timems*- wait (in milliseconds)*
• DWRITE pin,value - set pin with a value (HIGH,HI,LOW,LO)
• AWRITE pin,value - set pin with analog value (pwm) 0..255
• DREAD( pin ) - get the value of the pin
• AREAD( analogPin ) - get the value of the analog pin

Sound - Piezo wired with red/+ on pin 5 and black/- to ground

• TONE freq,timems - play "freq" for "timems" milleseconds (1000 = 1 second)
• TONEW freq,timems - same as above, but also waits for it to finish
• NOTONE - stop playback of all playing tones

Example programs

Here are a few example programs to get you started...

User Input

Let a user enter a new value for a variable, enter a number like '33' or '42', or a varaible like 'b'.

10 A=0
15 B=999
20 PRINT "A is ", A
30 PRINT "Enter a new value ";
40 INPUT A
50 PRINT "A is now ", A

Blink

hook up an LED between pin 3 and ground

10 FOR A=0 TO 10
20 DWRITE 3, HIGH
30 DELAY 250
40 DWRITE 3, LOW
50 DELAY 250
60 NEXT A

Fade

hook up an LED between pin 3 and ground

10 FOR A=0 TO 10
20 FOR B=0 TO 255
30 AWRITE 3, B
40 DELAY 10
50 NEXT B
60 FOR B=255 TO 0 STEP -1
70 AWRITE 3, B
80 DELAY 10
90 NEXT B
100 NEXT A

LED KNOB

hook up a potentiometeter between analog 2 and ground, led from digital 3 and ground. If knob is at 0, it stops

10 A = AREAD( 2 )
20 PRINT A
30 B = A / 4
40 AWRITE 3, B
50 IF A == 0 GOTO 100
60 GOTO 10
100 PRINT "Done."

Known Quirks and Limitations

• If LOAD or SAVE are called, FILES fails subsequent listings
• SD cards are not hot-swappable. A reset is required between swaps.