MEM.CRC16_generic (FUN)

MEM.CRC16_generic (FUN)

This function of the CAA_Memory.library calculates the check sum of a memory area in a generalized manner.

Input:

pMemoryBlock	DWORD	Address of memory area
uiLength	UINT	Size of area in bytes
wCRCInit	WORD	Initial value of check sum
wPoly	WORD	Polynomial of CRC algorithm
xReflectInput	BOOL	Reflect input bytes
xReflectOutput	BOOL	Reflect output bytes
wXORout	WORD	XOR Word preceeding output

Output:

MEM.CRC16_CCITT

WORD

check sum

Example:

sTest : STRING(10) := '123456789' ;

->

MEM.CRC16_generic(ADR(sTest),9,16#1021, FALSE, FALSE, 16#0000) = 16#29B1

Typical input parameters:

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