lib_crc.doc

来自「Port串行通信」· DOC 代码 · 共 41 行

   File      : lib_crc.doc
   Date      : 1999-02-21
   Author    : Lammert Bies
   E-mail    : [e-mail]
   Version   : 1.01

   Contents  : Documentation for the CRC functions in lib_crc.c



   The file lib_crc.c contains source code for functions to calculate
   the three most used CRC values: CRC-16, CRC-32 and CRC-CCITT. The
   functions can be freely used.

   To calculate a CRC, the following three steps must be followed:

   1. Initialize the CRC value. For CRC-16 and CRC-CCITT, the initial
      value of the CRC is 0. CRC-32 starts with an initial value
      of 0xffffffffL.

   2. For each byte of the data starting with the first byte, call the
      function update_crc_16(), update_crc_32() or update_crc_ccitt()
      to recalculate the value of the CRC.

   3. Only for CRC-32: When all bytes have been processed, take the
      one's complement of the obtained CRC value.



   An example of this calculation process can be found in the tst_crc.c
   sample program.



   The newest version of these files can be found at:

   http://www.lammertbies.nl/comm/software/download/lib_crc.zip