Diff: OneWireCRC.h

Revision:

0:21c0c97a5d7c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWireCRC.h	Thu Feb 03 12:10:20 2011 +0000
@@ -0,0 +1,138 @@
+/*
+* OneWireCRC. This is a port to mbed of Jim Studt's Adruino One Wire
+* library. Please see additional copyrights below this one, including
+* references to other copyrights.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireCRC.
+*
+* OneWireCRC is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireCRC is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireCRC.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/*
+Copyright (c) 2007, Jim Studt
+
+Updated to work with arduino-0008 and to include skip() as of
+2007/07/06. --RJL20
+
+Modified to calculate the 8-bit CRC directly, avoiding the need for
+the 256-byte lookup table to be loaded in RAM.  Tested in arduino-0010
+-- Tom Pollard, Jan 23, 2008
+
+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 THE AUTHORS OR COPYRIGHT HOLDERS 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.
+
+Much of the code was inspired by Derek Yerger's code, though I don't
+think much of that remains.  In any event that was..
+    (copyleft) 2006 by Derek Yerger - Free to distribute freely.
+
+The CRC code was excerpted and inspired by the Dallas Semiconductor 
+sample code bearing this copyright.
+*/
+//---------------------------------------------------------------------------
+// Copyright (C) 2000 Dallas Semiconductor Corporation, 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 DALLAS SEMICONDUCTOR 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 Dallas Semiconductor
+// shall not be used except as stated in the Dallas Semiconductor
+// Branding Policy.
+//--------------------------------------------------------------------------
+
+#ifndef SNATCH59_ONEWIRECRC_H
+#define SNATCH59_ONEWIRECRC_H
+
+#include <mbed.h>
+
+// Select the table-lookup method of computing the 8-bit CRC by setting this to 1
+#ifndef ONEWIRE_CRC8_TABLE
+#define ONEWIRE_CRC8_TABLE 1
+#endif
+
+typedef unsigned char BYTE;    // used to be uint8_t : something a byte wide, whatever ....
+
+enum eSpeed {OVERDRIVE, STANDARD};
+
+class OneWireCRC
+{
+public:
+    OneWireCRC(PinName oneWire, eSpeed);
+    
+    // reset, read, write functions
+    int reset();
+    void writeByte(int data);
+    int readByte();
+    int touchByte(int data);
+    void block(BYTE* data, int data_len);
+    int overdriveSkip(BYTE* data, int data_len);
+    
+    // address functions
+    void matchROM(BYTE rom[8]);
+    void skipROM();
+
+    // address search functions
+    void resetSearch();
+    BYTE search(BYTE* newAddr);
+
+    // CRC check functions
+    static BYTE crc8(BYTE* addr, BYTE len);
+    static unsigned short crc16(unsigned short* data, unsigned short len);
+
+private:
+    const int* timing;
+    
+    BYTE address[8];
+    int searchJunction;        // so we can set to it -1 somewhere
+    bool searchExhausted;
+    
+    DigitalInOut oneWirePort;
+    
+    // read/write bit functions
+    void writeBit(int bit);
+    int readBit();
+};
+
+#endif