Diff: OneWire_Masters/RomId.cpp

Revision:

17:b646b1e3970b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWire_Masters/RomId.cpp	Fri Mar 18 20:21:05 2016 +0000
@@ -0,0 +1,64 @@
+/******************************************************************//**
+* Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a
+* copy of this software and associated documentation files (the "Software"),
+* to deal in the Software without restriction, including without limitation
+* the rights to use, copy, modify, merge, publish, distribute, sublicense,
+* and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included
+* in all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+* IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+* OTHER DEALINGS IN THE SOFTWARE.
+*
+* Except as contained in this notice, the name of Maxim Integrated
+* Products, Inc. shall not be used except as stated in the Maxim Integrated
+* Products, Inc. Branding Policy.
+*
+* The mere transfer of this software does not imply any licenses
+* of trade secrets, proprietary technology, copyrights, patents,
+* trademarks, maskwork rights, or any other form of intellectual
+* property whatsoever. Maxim Integrated Products, Inc. retains all
+* ownership rights.
+**********************************************************************/
+
+
+#include "RomId.hpp"
+
+
+//--------------------------------------------------------------------------
+// Calculate the CRC8 of the byte value provided with the current 
+// global 'crc8' value. 
+// Returns current global crc8 value
+//
+uint8_t RomId::calculateCRC8(uint8_t crc8, uint8_t data)
+{
+   int i; 
+
+   // See Application Note 27
+   crc8 = crc8 ^ data;
+   for (i = 0; i < 8; ++i)
+   {
+      if (crc8 & 1)
+         crc8 = (crc8 >> 1) ^ 0x8c;
+      else
+         crc8 = (crc8 >> 1);
+   }
+
+   return crc8;
+}
+
+uint8_t RomId::calculateCRC8(const uint8_t * data, size_t data_len, uint8_t crc)
+{
+  for (size_t i = 0; i < data_len; i++)
+    crc = calculateCRC8(crc, data[i]);
+  return crc;
+}