Файл: Fast AVR. Basic compiller for AVR. User manual (2004).pdf

FastAVR Basic compiler Manual

Many expressions are supported in FastAVR. From very basic assignments like: a=5

To more complex like: a=(b+12)*c-3*d

FastAVR Basic Compiler performs all math operations in full hierarchal order. This means there is precedence to the operators. Multiplication and division are performed before addition and subtractions. As an example, to ensure the operations are carried out in the order needed, use parentheses to group the operations.

Even calls to system and user functions can be factors in expressions: a=5*Test(15)+Adc8(3)

Where Test is your function called with parameter 15 and Adc8(3) is a system function that returns an 8bit value as a result of the analog measurement on channel 3.

List of mathematical operators:

+ plus sign

-minus sign

* asterisk (multiplication symbol) / slash (division symbol)

Mod modulus operator

List of relational operators:

<less than

>greater than

List of logical operators:

And conjunction

Or disjunction

List of boolean operators:

And, & boolean conjunction, bitwise and

Other operators also have special meanings, such as:

" double quotation as string delimiters , comma as a parameter separator

. period for ports or variable bit delimiters

; semicolon is used when more than one parameter is used (i.e., Print a; b; c) ' single quotation mark starts a comment

Numeric constants can be in decimal format: a=33

in hexadecimal:

a=&h21 'dec 33

or even in bynary: a=&b00100001 'dec 33

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FastAVR Basic compiler Manual

A Label can be used as a line identifier. Label is an alphanumeric combination ending with a colon.

If a=0 Then

Goto ExitLabel

After the main loop we write all used and previously declared subs and functions, including interrupt subroutines.

The subroutine itself starts with the keyword Sub or Function, followed by the name and parameter list (if one exists)

Sub Test1(a As Byte, b As Word)

Function Test2(a As Byte, b As Byte) as Byte

Parameter list must be identical to the declaration of the sub!

With the keyword Local we can declare local variables.

Local var as Type

Bits, Strings and Arrays are always Global!

The use and lifetime of local variables are limited to this subroutine.

The rules for Type are the same as for the Dim.

The body of Sub or Function is a complete program needed to solve a particular problem. The Function can return a value using the keyword Return.

If you have serious trouble in programming, especially if in doubt about the compiled results, please email source files to the mailing list for support!

FastAVR HINTS!

All internal registers can be accessed direct from basic:

MemCopy(16, Str_0+16*n, s) ' copies n-th string from Str_0 into string s (acts like Array of Strings!)

Str_2="FastAVR"

n=Str_2(4) ' n=65 Strings acts like Arrays - elements are accessable also by index

Happy programming!

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FastAVR Basic compiler Manual

2.14.Interrupts

All AVR interrupts are supported by FastAVR!

Interrupt Ovf1(), Save All

Interrupt service routines are just like normal subroutines. Of course, instead of using the keyword Sub we will use Interrupt. The table of short names listed below may be used for Interrupt names!

Very important is the Save x directive. Save x determines how many registers will be saved before calling the interrupt. This depends on what variables are used in the routine.

Save 0, will save SREG only, could be omitted, Save 1, will save SREG, zl and zh only.

Save 2, as Save 0 plus r24 and r25 Save 3, as Save 1 plus r0, r1, xl and xh

Save 4, as Save 2 plus r0, r1, r20, r21, r22, r23, xl and xh

Save All will save SREG and all registers from r0 to r5 and r19 to r31

When the Interrupt routine is more complex, use Save 2, Save 3 or Save All.

'/////////////////////////////////////////////////////

When user dont know about using Save, start with All and then try the minor versions!

Here is a list of available Interrupts

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FastAVR Basic compiler Manual

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