Diff: nordic-sdk/components/libraries/util/app_util.h

Revision:

103:138bdc859cc9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nordic-sdk/components/libraries/util/app_util.h	Wed Apr 15 08:59:11 2015 +0100
@@ -0,0 +1,232 @@
+/* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
+ *
+ * The information contained herein is property of Nordic Semiconductor ASA.
+ * Terms and conditions of usage are described in detail in NORDIC
+ * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
+ *
+ * Licensees are granted free, non-transferable use of the information. NO
+ * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
+ * the file.
+ *
+ */
+
+/** @file
+ *
+ * @defgroup app_util Utility Functions and Definitions
+ * @{
+ * @ingroup app_common
+ *
+ * @brief Various types and definitions available to all applications.
+ */
+
+#ifndef APP_UTIL_H__
+#define APP_UTIL_H__
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "compiler_abstraction.h"
+
+enum
+{
+    UNIT_0_625_MS = 625,                                /**< Number of microseconds in 0.625 milliseconds. */
+    UNIT_1_25_MS  = 1250,                               /**< Number of microseconds in 1.25 milliseconds. */
+    UNIT_10_MS    = 10000                               /**< Number of microseconds in 10 milliseconds. */
+};
+
+/**@brief Macro for doing static (i.e. compile time) assertion.
+ *
+ * @note If the assertion fails when compiling using Keil, the compiler will report error message
+ *       "error: #94: the size of an array must be greater than zero" (while gcc will list the
+ *       symbol static_assert_failed, making the error message more readable).
+ *       If the supplied expression can not be evaluated at compile time, Keil will report
+ *       "error: #28: expression must have a constant value".
+ *
+ * @note The macro is intentionally implemented not using do while(0), allowing it to be used
+ *       outside function blocks (e.g. close to global type- and variable declarations).
+ *       If used in a code block, it must be used before any executable code in this block.
+ *
+ * @param[in]   EXPR   Constant expression to be verified.
+ */
+
+#if defined(__GNUC__)
+#define STATIC_ASSERT(EXPR) typedef char __attribute__((unused)) static_assert_failed[(EXPR) ? 1 : -1]
+#else
+#define STATIC_ASSERT(EXPR) typedef char static_assert_failed[(EXPR) ? 1 : -1]
+#endif
+
+
+/**@brief type for holding an encoded (i.e. little endian) 16 bit unsigned integer. */
+typedef uint8_t uint16_le_t[2];
+
+/**@brief type for holding an encoded (i.e. little endian) 32 bit unsigned integer. */
+typedef uint8_t uint32_le_t[4];
+
+/**@brief Byte array type. */
+typedef struct
+{
+    uint16_t  size;                 /**< Number of array entries. */
+    uint8_t * p_data;               /**< Pointer to array entries. */
+} uint8_array_t;
+    
+/**@brief Perform rounded integer division (as opposed to truncating the result).
+ *
+ * @param[in]   A   Numerator.
+ * @param[in]   B   Denominator.
+ *
+ * @return      Rounded (integer) result of dividing A by B.
+ */
+#define ROUNDED_DIV(A, B) (((A) + ((B) / 2)) / (B))
+
+/**@brief Check if the integer provided is a power of two.
+ *
+ * @param[in]   A   Number to be tested.
+ *
+ * @return      true if value is power of two.
+ * @return      false if value not power of two.
+ */
+#define IS_POWER_OF_TWO(A) ( ((A) != 0) && ((((A) - 1) & (A)) == 0) )
+
+/**@brief To convert milliseconds to ticks.
+ * @param[in] TIME          Number of milliseconds to convert.
+ * @param[in] RESOLUTION    Unit to be converted to in [us/ticks].
+ */
+#define MSEC_TO_UNITS(TIME, RESOLUTION) (((TIME) * 1000) / (RESOLUTION))
+
+
+/**@brief Perform integer division, making sure the result is rounded up.
+ *
+ * @details One typical use for this is to compute the number of objects with size B is needed to
+ *          hold A number of bytes.
+ *
+ * @param[in]   A   Numerator.
+ * @param[in]   B   Denominator.
+ *
+ * @return      Integer result of dividing A by B, rounded up.
+ */
+#define CEIL_DIV(A, B)      \
+    /*lint -save -e573 */   \
+    ((((A) - 1) / (B)) + 1) \
+    /*lint -restore */
+
+/**@brief Function for encoding a uint16 value.
+ *
+ * @param[in]   value            Value to be encoded.
+ * @param[out]  p_encoded_data   Buffer where the encoded data is to be written.
+ *
+ * @return      Number of bytes written.
+ */
+static __INLINE uint8_t uint16_encode(uint16_t value, uint8_t * p_encoded_data)
+{
+    p_encoded_data[0] = (uint8_t) ((value & 0x00FF) >> 0);
+    p_encoded_data[1] = (uint8_t) ((value & 0xFF00) >> 8);
+    return sizeof(uint16_t);
+}
+    
+/**@brief Function for encoding a uint32 value.
+ *
+ * @param[in]   value            Value to be encoded.
+ * @param[out]  p_encoded_data   Buffer where the encoded data is to be written.
+ *
+ * @return      Number of bytes written.
+ */
+static __INLINE uint8_t uint32_encode(uint32_t value, uint8_t * p_encoded_data)
+{
+    p_encoded_data[0] = (uint8_t) ((value & 0x000000FF) >> 0);
+    p_encoded_data[1] = (uint8_t) ((value & 0x0000FF00) >> 8);
+    p_encoded_data[2] = (uint8_t) ((value & 0x00FF0000) >> 16);
+    p_encoded_data[3] = (uint8_t) ((value & 0xFF000000) >> 24);
+    return sizeof(uint32_t);
+}
+
+/**@brief Function for decoding a uint16 value.
+ *
+ * @param[in]   p_encoded_data   Buffer where the encoded data is stored.
+ *
+ * @return      Decoded value.
+ */
+static __INLINE uint16_t uint16_decode(const uint8_t * p_encoded_data)
+{
+        return ( (((uint16_t)((uint8_t *)p_encoded_data)[0])) | 
+                 (((uint16_t)((uint8_t *)p_encoded_data)[1]) << 8 ));
+}
+
+/**@brief Function for decoding a uint32 value.
+ *
+ * @param[in]   p_encoded_data   Buffer where the encoded data is stored.
+ *
+ * @return      Decoded value.
+ */
+static __INLINE uint32_t uint32_decode(const uint8_t * p_encoded_data)
+{
+    return ( (((uint32_t)((uint8_t *)p_encoded_data)[0]) << 0)  |
+             (((uint32_t)((uint8_t *)p_encoded_data)[1]) << 8)  |
+             (((uint32_t)((uint8_t *)p_encoded_data)[2]) << 16) |
+             (((uint32_t)((uint8_t *)p_encoded_data)[3]) << 24 ));
+}
+    
+/** @brief Function for converting the input voltage (in milli volts) into percentage of 3.0 Volts.
+ *
+ *  @details The calculation is based on a linearized version of the battery's discharge
+ *           curve. 3.0V returns 100% battery level. The limit for power failure is 2.1V and
+ *           is considered to be the lower boundary.
+ *
+ *           The discharge curve for CR2032 is non-linear. In this model it is split into
+ *           4 linear sections:
+ *           - Section 1: 3.0V - 2.9V = 100% - 42% (58% drop on 100 mV)
+ *           - Section 2: 2.9V - 2.74V = 42% - 18% (24% drop on 160 mV)
+ *           - Section 3: 2.74V - 2.44V = 18% - 6% (12% drop on 300 mV)
+ *           - Section 4: 2.44V - 2.1V = 6% - 0% (6% drop on 340 mV)
+ *
+ *           These numbers are by no means accurate. Temperature and
+ *           load in the actual application is not accounted for!
+ *
+ *  @param[in] mvolts The voltage in mV
+ *
+ *  @return    Battery level in percent.
+*/
+static __INLINE uint8_t battery_level_in_percent(const uint16_t mvolts)
+{
+    uint8_t battery_level;
+
+    if (mvolts >= 3000)
+    {
+        battery_level = 100;
+    }
+    else if (mvolts > 2900)
+    {
+        battery_level = 100 - ((3000 - mvolts) * 58) / 100;
+    }
+    else if (mvolts > 2740)
+    {
+        battery_level = 42 - ((2900 - mvolts) * 24) / 160;
+    }
+    else if (mvolts > 2440)
+    {
+        battery_level = 18 - ((2740 - mvolts) * 12) / 300;
+    }
+    else if (mvolts > 2100)
+    {
+        battery_level = 6 - ((2440 - mvolts) * 6) / 340;
+    }
+    else
+    {
+        battery_level = 0;
+    }
+
+    return battery_level;
+}
+
+/**@brief Function for checking if a pointer value is aligned to a 4 byte boundary.
+ *
+ * @param[in]   p   Pointer value to be checked.
+ *
+ * @return      TRUE if pointer is aligned to a 4 byte boundary, FALSE otherwise.
+ */
+static __INLINE bool is_word_aligned(void * p)
+{
+    return (((uintptr_t)p & 0x03) == 0);
+}
+
+#endif // APP_UTIL_H__
+
+/** @} */
\ No newline at end of file