P1-Meter-ESP8266/CRC16.h
2016-01-28 19:38:51 +01:00

29 lines
662 B
C

#ifndef CRC16_H
#define CRC16_H
#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
unsigned int CRC16(unsigned int crc, unsigned char *buf, int len)
{
for (int pos = 0; pos < len; pos++)
{
crc ^= (unsigned int)buf[pos]; // XOR byte into least sig. byte of crc
for (int i = 8; i != 0; i--) { // Loop over each bit
if ((crc & 0x0001) != 0) { // If the LSB is set
crc >>= 1; // Shift right and XOR 0xA001
crc ^= 0xA001;
}
else // Else LSB is not set
crc >>= 1; // Just shift right
}
}
return crc;
}
#endif