36 lines
996 B
C
36 lines
996 B
C
// Thanks to atc1441
|
|
// https://gist.github.com/atc1441/41af75048e4c22af1f5f0d4c1d94bb56
|
|
|
|
#include <stdint.h>
|
|
|
|
uint16_t CRC16(uint16_t crc, uint8_t *buffer, int len) // Default CRC16 Algo
|
|
{
|
|
while(len--)
|
|
{
|
|
crc ^= *buffer++ << 8;
|
|
int bits = 0;
|
|
do
|
|
{
|
|
if ( (crc & 0x8000) != 0 )
|
|
crc = (2 * crc) ^ 0x1021;
|
|
else
|
|
crc *= 2;
|
|
}
|
|
while ( ++bits < 8 );
|
|
}
|
|
return crc;
|
|
}
|
|
|
|
//uint8_t nfctag_uid[] = {0x04,0xEC,0xFC,0xA2,0x94,0x10,0x90}; // NTAG UID
|
|
//uint8_t nfc_second[] = "221214 12K"; // Head MFG String, printed on Head and at memory location 0x23
|
|
|
|
uint32_t get_sonicare_password(uint8_t nfctag_uid[], uint8_t nfc_second[]) {
|
|
uint32_t crc_calc = CRC16(0x49A3, nfctag_uid, 7); // Calculate the NTAG UID CRC
|
|
|
|
crc_calc = crc_calc | (CRC16(crc_calc, nfc_second, 10) << 16); // Calculate the MFG CRC
|
|
|
|
crc_calc = ((((crc_calc >> 8) & 0x00FF00FF) | (crc_calc << 8)) & 0xFF00FF00); // Rotate the uin16_t bytes
|
|
|
|
return crc_calc;
|
|
}
|