crc16 with word & byte--查表法

#1, BYTE CRC
参考：
https://blog.youkuaiyun.com/m0_37697335/article/details/113267780?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522F1451286-1B97-44AA-A5FC-386045B4939B%2522%252C%2522scm%2522%253A%252220140713.130102334…%2522%257D&request_id=F1451286-1B97-44AA-A5FC-386045B4939B&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2_allsobaiduend~default-1-113267780-null-null.142^v100pc_search_result_base9&utm_term=crc16%20modbus%E6%9F%A5%E8%A1%A8%E6%B3%95%20c%E8%AF%AD%E8%A8%80&spm=1018.2226.3001.4187
注意表格不对，会有错误。

/MODBUS******************

• Name: CRC-16/MODBUS x16+x15+x2+1

• Width: 16

• Poly: 0x8005

• Init: 0xFFFF

• Refin: True

• Refout: True

• Xorout: 0x0000

• Note:
  *****************************************************************************/
  WORD CRC_GetModbus16(BYTE * pData, WORD nLength)
  {
  WORD cRc_16 = 0xFFFF, i;
  BYTE temp;

  for (i = 0; i < nLength; ++i)
  {
  temp = (BYTE)(cRc_16 & 0xFF);
  cRc_16 = (WORD)((cRc_16 >> 8) ^ crc16tab[(temp ^ pData[i]) & 0xFF]);

  }

  return cRc_16;
  }
  #2， WORD CRC