Diff: rfal_crc.cpp

Revision:

0:75fc82583a41

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rfal_crc.cpp	Thu Nov 14 14:34:50 2019 +0000
@@ -0,0 +1,83 @@
+
+/******************************************************************************
+  * @attention
+  *
+  * <h2><center>&copy; COPYRIGHT 2016 STMicroelectronics</center></h2>
+  *
+  * Licensed under ST MYLIBERTY SOFTWARE LICENSE AGREEMENT (the "License");
+  * You may not use this file except in compliance with the License.
+  * You may obtain a copy of the License at:
+  *
+  *        http://www.st.com/myliberty
+  *
+  * Unless required by applicable law or agreed to in writing, software 
+  * distributed under the License is distributed on an "AS IS" BASIS, 
+  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied,
+  * AND SPECIFICALLY DISCLAIMING THE IMPLIED WARRANTIES OF MERCHANTABILITY,
+  * FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+  * See the License for the specific language governing permissions and
+  * limitations under the License.
+  *
+******************************************************************************/
+
+/*
+ *      PROJECT:   ST25R391x firmware
+ *      $Revision: $
+ *      LANGUAGE:  ISO C99
+ */
+
+/*! \file rfal_crc.c
+ *
+ *  \author Oliver Regenfelder
+ *
+ *  \brief CRC calculation implementation
+ *
+ */
+
+/*
+******************************************************************************
+* INCLUDES
+******************************************************************************
+*/
+#include "rfal_crc.h"
+
+/*
+******************************************************************************
+* LOCAL FUNCTION PROTOTYPES
+******************************************************************************
+*/
+static uint16_t rfalCrcUpdateCcitt(uint16_t crc, uint8_t dat);
+
+/*
+******************************************************************************
+* GLOBAL FUNCTIONS
+******************************************************************************
+*/
+uint16_t rfalCrcCalculateCcitt(uint16_t preloadValue, const uint8_t* buf, uint16_t length)
+{
+    uint16_t crc = preloadValue;
+    uint16_t index;
+
+    for (index = 0; index < length; index++)
+    {
+        crc = rfalCrcUpdateCcitt(crc, buf[index]);
+    }
+
+    return crc;
+}
+
+/*
+******************************************************************************
+* LOCAL FUNCTIONS
+******************************************************************************
+*/
+static uint16_t rfalCrcUpdateCcitt(uint16_t crc, uint8_t dat)
+{
+    dat ^= ((uint8_t)crc) & 0xFF;
+    dat ^= dat << 4;
+
+    crc = (crc >> 8)^(((uint16_t) dat) << 8)^(((uint16_t) dat) << 3)^(((uint16_t) dat) >> 4);
+
+    return crc;
+}
+