CRC16_generic (FUN)

FUNCTION CRC16_generic : WORD

Function calculates the checksum CRC16 of the "MemoryBlock" in a generalized manner.

Typical input parameter:

• CRC16 standard :

  • wCRCInit := 16#0000

  • wPoly := 16#8005

  • xReflectInput := TRUE

  • xReflectOutput := TRUE

  • wXORout := 16#0000

• CRC16-CCITT :

  • wCRCInit := 16#FFFF

  • wPoly := 16#1021

  • xReflectInput := FALSE

  • xReflectOutput := FALSE

  • wXORout := 16#0000

• CRC16-Modbus :

  • wCRCInit := 16#FFFF

  • wPoly := 16#8005

  • xReflectInput := TRUE

  • xReflectOutput := TRUE

  • wXORout := 16#0000

Example:

sTest : STRING(10) := '123456789' ;
->
MEM.CRC16_generic(ADR(sTest),9,16#1021, FALSE, FALSE, 16#0000) = 16#29B1

InOut:

Scope Name Type Comment Return CRC16_generic WORD function returns generalized CRC16 of "MemoryBlock" Input pMemoryBlock POINTER TO BYTE address of memory Block uiLength UINT length of MemoryBlock in byte wCRCInit WORD initial value for CRC value wPoly WORD polynom value for CRC algorithm xReflectInput BOOL reflect input data bytes xReflectOutput BOOL reflect CRC before final XOR wXORout WORD final XOR value before output