Revision 0:cc65a6cec1a1, committed 2010-10-21

Comitter:

evwijk

Date:

Thu Oct 21 17:11:49 2010 +0000

Commit message:

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/crc8.cpp	Thu Oct 21 17:11:49 2010 +0000
@@ -0,0 +1,64 @@
+/* please read copyright-notice at EOF */
+
+#include "crc8.h"
+
+#define CRC8INIT    0x00
+#define CRC8POLY    0x18              //0X18 = X^8+X^5+X^4+X^0
+
+char    crc8 ( char *data_in, int number_of_bytes_to_read )
+{
+    char     crc;
+    int loop_count;
+    char  bit_counter;
+    char  data;
+    char  feedback_bit;
+    
+    crc = CRC8INIT;
+
+    for (loop_count = 0; loop_count != number_of_bytes_to_read; loop_count++)
+    {
+        data = data_in[loop_count];
+        
+        bit_counter = 8;
+        do {
+            feedback_bit = (crc ^ data) & 0x01;
+    
+            if ( feedback_bit == 0x01 ) {
+                crc = crc ^ CRC8POLY;
+            }
+            crc = (crc >> 1) & 0x7F;
+            if ( feedback_bit == 0x01 ) {
+                crc = crc | 0x80;
+            }
+        
+            data = data >> 1;
+            bit_counter--;
+        
+        } while (bit_counter > 0);
+    }
+    
+    return crc;
+}
+
+/*
+This code is from Colin O'Flynn - Copyright (c) 2002 
+only minor changes by M.Thomas 9/2004
+oonverted to mbed library by Erik van Wijk 10/2010
+
+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.
+*/

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/crc8.h	Thu Oct 21 17:11:49 2010 +0000
@@ -0,0 +1,29 @@
+#ifndef CRC8_H_
+#define CRC8_H_
+
+char	crc8 (char* data_in, int number_of_bytes_to_read);
+
+#endif
+
+/*
+This is based on code from :
+
+Copyright (c) 2002 Colin O'Flynn
+
+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.
+*/