crc.c

TI公司的低功耗设计

/***********************************************************************************
    Filename: crc.c

    Copyright 2008 Texas Instruments, Inc.
***********************************************************************************/

#include <hal_types.h>
#include <hal_defs.h>
#include <crc.h>



//-------------------------------------------------------------------------------------------------------
//  uint16 crcCalc(uint16 crcReg, uint8 crcData) 
//
//  DESCRIPTION:
//      Calculates the 16-bit CRC. The function requires that the CRC_POLYNOM is defined,
//      which gives the wanted CRC polynom. 
//
//  ARGUMENTS: 
//      uint8  crcData  - Data to perform the CRC-16 operation on.
//      uint16 crcReg   - Current or initial value of the CRC calculation
//
//  RETURN:
//      The value returned is the 16-bit CRC (of the data supplied so far). 
//-------------------------------------------------------------------------------------------------------

uint16 crcCalc(uint16 crcReg, uint8 crcData) 
{
  uint8 i;

  for (i = 0; i < 8; i++) 
  {
    // If upper most bit is 1
    if (((crcReg & 0x8000) >> 8) ^ (crcData & 0x80))
      crcReg = (crcReg << 1)  ^ CRC_POLYNOM;
    else
      crcReg = (crcReg << 1);

    crcData <<= 1;
  }
  
  return crcReg;
}



/***********************************************************************************
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  YOU FURTHER ACKNOWLEDGE AND AGREE THAT THE SOFTWARE AND DOCUMENTATION ARE
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