Headeruart And Traileruart Definitions; Cyclic Redundancy Checks; Compute; Sample In C - envea CAIRSENS PM Série Notice Technique

0x12
0x1C
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HeaderUart and TrailerUart definitions

In the following section of this document, the series of bytes representing SYNC STX LG and a part of
CMD will be referred to as HeaderUart and will be defined by:
· HeaderUart = SYNC, STX, LG, 0x30, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06
In the same idea, the series of bytes representing END will be referred to as TrailerUart and will be
defined by:
· TrailerUart = END CRC ETX
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Cyclic redundancy checks

6.1

Compute

The CRC code is calculated by dividing the binary sequence representing the frame by the following
polynomial:
16 12
X + X + X
6.2

Sample in c

#include <stdio.h>
unsigned int
{
unsigned int
unsigned int
unsigned char
Crc=0;
for (j=0;j<lg; j++) {
Crc = Crc ^ Frame[j];
for ( i_bits = 0; i_bits < 8; i_bits++ ) {
carry = Crc & 1;
Crc = Crc/2;
if(carry) {
Crc = Crc ^ Poly;
}
}
}
return Crc;
}
int main(int
{
unsigned int
unsigned char
0x02,// Start Frame
0x13,// Length of Data
0x30,0x01,0x02,0x03,0x04,0x05,0x06,
© 2016 Cairpol
Get the last minute average data ( 1 data returned )
Get stored average data ( multiple data returned )
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+ 1
FCRC( unsigned char Frame[],unsigned char
Poly = 0x8408;
Crc;
j,i_bits,carry;
argc, char* argv[])
i;
Frame[] = {0xFF, // Synchro Word
Available commands
lg)
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