Symbols

The Symbol directive provides a method for aliasing variables and/or constants. Symbol cannot be used to create a variable. Constants declared using Symbol do not use any RAM within the microcontroller.

Symbol cCat = 123
Symbol cTiger = cCat                ' cTiger now holds the value of cCat
Symbol cMouse = 1
Symbol cTigOuse = (cTiger + cMouse)  ' Add cTiger to cMouse to make cTigOuse

FloatIng point constants may also be created using Symbol by simply adding a decimal point to a value.

Symbol cPI = 3.14   ' Create a floating point constant named cPI
Symbol cFlNum = 5.0   ' Create a floating point constant holding the value 5.0

FloatIng point constant can also be created using expressions.

' Create a floating point constant holding the result of the expression
Symbol cQuanta = (3.3 / 1024)

If a variable or SFR's name is used in a constant expression then the variable's or SFR's address will be substituted, not the value held in the variable or SFR: -

Symbol cMyCon = (PORTB + 1)  ' MyCon will hold the value 715 (714+1)

Symbol is also useful for aliasing Ports and SFRs (Special Function Registers): -

Symbol LED_Pin = PORTA.1     ' LED_Pin now references bit-1 of PORTA
Symbol cOSCFAIL = INTCON1.1  ' cOSCFAIL now refers to bit-1 of INTCON1 SFR

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