WhyCan Forum(哇酷开发者社区)

一定要用标准的CRC吗？

或者校验和

是的, 标准的。

做通用系统，
非标就自己弄一个算法，
我也用过校验和, 8位的

累加对连续的位翻转无能为力.

我觉得按字节累加还好一些。
因为同时两个字节互换错误的概率不大呀。

查表后还不是得异或？

也有一种不查表一次计算8位的，
时间空间各有优势。

维基百科
https://en.wikipedia.org/wiki/Computation_of_cyclic_redundancy_checks

Computation of a cyclic redundancy check is derived from the mathematics of polynomial division, modulo two. In practice, it resembles long division of the binary message string, with a fixed number of zeroes appended, by the "generator polynomial" string except that exclusive OR operations replace subtractions. Division of this type is efficiently realised in hardware by a modified shift register,[1] and in software by a series of equivalent algorithms, starting with simple code close to the mathematics and becoming faster (and arguably more obfuscated[2]) through byte-wise parallelism and space-time tradeoffs.

Example of generating an 8-bit CRC. The generator is a Galois type shift register with xor gates placed according to powers (white numbers) of x in the generator polynomial. The message stream may be any length. After it has been shifted through the register, followed by 8 zeroes, the result in the register is the checksum.

Checking received data with checksum. The received message is shifted through the same register as used in the generator, but the received checksum is attached to it instead of zeroes. Correct data yields the all-zeroes result; a corrupted bit in either the message or checksum would give a different result, warning that an error has occurred.
Various CRC standards extend the polynomial division algorithm by specifying an initial shift register value, a final exclusive OR step and, most critically, a bit ordering (endianness). As a result, the code seen in practice deviates confusingly from "pure" division,[2] and the register may shift left or right.

不加校验的也用过，嘿嘿

刷个分吧

16位校验和搞定

CRC

简单点的累加和，或者靠谱点CRC校验。

顶！学习了。

我一般使用CRC

一般的指令通信用校验和就好了，数据包较大的上百字节的会用上CRC，大文件10KB级别的上MD5

通信从不校验的飘过。

看你误码率。误码率低的话可以CRC，误码率高的话可能得考虑前向纠错，比如Hsiao算法。缺点嘛，就是数据必须成块，而且块越小，ECC校验位占的带宽越高。