SICK LD-OEM Betriebsanleitung Seite 79

Betriebsanleitung
Lasermesssystem LD OEM
Function: block_crc16_word
Abstract: calculates CRC16 signature of a block of data words (16bit)
Version: 1
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Return value:
type functional description
WORD CRC signature
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Importlist:
type identifier
WORD* data
WORD numofbytes
WORD initial_crc
WORD[] crctab
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Exportlist:
type identifier
none
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*/
PUBLIC WORD block_crc16_word
(
WORD* data,
WORD numofbytes,
WORD initial_crc
)
{
register WORD d;
register WORD crc = initial_crc;
numofbytes >>= 1;
while( numofbytes-- )
{
d = *data++;
crc = ( (crc << 8) | ((BYTE)( d >> 8 ) ) ) ^ crctab[crc>>8];
crc = ( (crc << 8) | ((BYTE)
}
return crc;
}
/*
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Function: crc16_byte
Abstract: calculates CRC16 signature of a single data byte
8 010 327/0000/28-09-2004
Anhang
functional description
pointer to data block
number of bytes (not words!) in data block
initial CRC value
CRC XOR table (as global variable)
functional description
d
© SICK AG · Division Auto Ident · Germany · All rights reserved
)) ^ crctab[crc>>8];
Kapitel 10
10-15