Created
June 1, 2020 21:24
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Galaxy Buds - Payload Checksum Calculator
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/****************************************************************************** | |
Samsung Galaxy Buds RFComm Transmission CRC16 (CCITT) Algorithm | |
*******************************************************************************/ | |
#include <stdio.h> | |
int | |
main () | |
{ | |
int crc16tab[] = | |
{ 0, 4129, 8258, 12387, 16516, 20645, 24774, 28903, 33032, 37161, 41290, | |
45419, 49548, 53677, 57806, 61935, 4657, 528, 12915, 8786, 21173, 17044, 29431, 25302, | |
37689, 33560, 45947, 41818, 54205, 50076, 62463, 58334, 9314, 13379, 1056, 5121, 25830, | |
29895, 17572, 21637, 42346, 46411, 34088, 38153, 58862, 62927, 50604, 54669, 13907, | |
9842, 5649, 1584, 30423, 26358, 22165, 18100, 46939, 42874, 38681, 34616, 63455, 59390, | |
55197, 51132, 18628, 22757, 26758, 30887, 2112, 6241, 10242, 14371, 51660, 55789, | |
59790, 63919, 35144, 39273, 43274, 47403, 23285, 19156, 31415, 27286, 6769, 2640, | |
14899, 10770, 56317, 52188, 64447, 60318, 39801, 35672, 47931, 43802, 27814, 31879, | |
19684, 23749, 11298, 15363, 3168, 7233, 60846, 64911, 52716, 56781, 44330, 48395, | |
36200, 40265, 32407, 28342, 24277, 20212, 15891, 11826, 7761, 3696, 65439, 61374, | |
57309, 53244, 48923, 44858, 40793, 36728, 37256, 33193, 45514, 41451, 53516, 49453, | |
61774, 57711, 4224, 161, 12482, 8419, 20484, 16421, 28742, 24679, 33721, 37784, 41979, | |
46042, 49981, 54044, 58239, 62302, 689, 4752, 8947, 13010, 16949, 21012, 25207, 29270, | |
46570, 42443, 38312, 34185, 62830, 58703, 54572, 50445, 13538, 9411, 5280, 1153, 29798, | |
25671, 21540, 17413, 42971, 47098, 34713, 38840, 59231, 63358, 50973, 55100, 9939, | |
14066, 1681, 5808, 26199, 30326, 17941, 22068, 55628, 51565, 63758, 59695, 39368, | |
35305, 47498, 43435, 22596, 18533, 30726, 26663, 6336, 2273, 14466, 10403, 52093, | |
56156, 60223, 64286, 35833, 39896, 43963, 48026, 19061, 23124, 27191, 31254, 2801, | |
6864, 10931, 14994, 64814, 60687, 56684, 52557, 48554, 44427, 40424, 36297, 31782, | |
27655, 23652, 19525, 15522, 11395, 7392, 3265, 61215, 65342, 53085, 57212, 44955, | |
49082, 36825, 40952, 28183, 32310, 20053, 24180, 11923, 16050, 3793, 7920 }; | |
/* | |
* Original Payload: | |
* {0x61, 0x02, 0x00, 0x4B, 0x5F, 0x01, 0x00, 0x00, 0x00, 0x01, 0x05, 0x00, 0x02, 0x00, 0x13, 0x0F, 0xF3} | |
* ^MsgID ^Payload-Content ^CRC1 ^CRC2 | |
* | |
* NOTE: Both CRC values need to be swapped before calculating the checksum! | |
*/ | |
char data[] = {0x61, 0x02, 0x00, 0x4B, 0x5F, 0x01, 0x00, 0x00, 0x00, 0x01, 0x05, 0x00, 0x02, 0x00, 0x13, 0xF3, 0x0F}; | |
int i2 = 0; | |
for (int i3 = 0; i3 < sizeof(data); i3++) | |
i2 = crc16tab[((i2 >> 8) ^ data[i3]) & 255] ^ (i2 << 8); | |
printf ("Dec: %d, Hex: 0x%x",65535 & i2, 65535 & i2); | |
return 0; | |
} |
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