app_util.h

00001 /* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
00002  *
00003  * The information contained herein is property of Nordic Semiconductor ASA.
00004  * Terms and conditions of usage are described in detail in NORDIC
00005  * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
00006  *
00007  * Licensees are granted free, non-transferable use of the information. NO
00008  * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
00009  * the file.
00010  *
00011  */
00012 
00013 /** @file
00014  *
00015  * @defgroup app_util Utility Functions and Definitions
00016  * @{
00017  * @ingroup app_common
00018  *
00019  * @brief Various types and definitions available to all applications.
00020  */
00021 
00022 #ifndef APP_UTIL_H__
00023 #define APP_UTIL_H__
00024 
00025 #include <stdint.h>
00026 #include "nordic_global.h"
00027 #include "compiler_abstraction.h"
00028 #include "nrf51.h"
00029 #include "app_error.h "
00030 
00031 /**@brief The interrupt priorities available to the application while the softdevice is active. */
00032 typedef enum
00033 {
00034     APP_IRQ_PRIORITY_HIGH = 1,
00035     APP_IRQ_PRIORITY_LOW  = 3
00036 } app_irq_priority_t;
00037 
00038 enum
00039 {
00040     UNIT_0_625_MS = 625,                                /**< Number of microseconds in 0.625 milliseconds. */
00041     UNIT_1_25_MS  = 1250,                               /**< Number of microseconds in 1.25 milliseconds. */
00042     UNIT_10_MS    = 10000                               /**< Number of microseconds in 10 milliseconds. */
00043 };
00044 
00045 #define NRF_APP_PRIORITY_THREAD    4                    /**< "Interrupt level" when running in Thread Mode. */
00046 
00047 /**@cond NO_DOXYGEN */
00048 #define EXTERNAL_INT_VECTOR_OFFSET 16
00049 /**@endcond */
00050 
00051 #define PACKED(TYPE) __packed TYPE
00052 
00053 /**@brief Macro for doing static (i.e. compile time) assertion.
00054  *
00055  * @note If the assertion fails when compiling using Keil, the compiler will report error message
00056  *       "error: #94: the size of an array must be greater than zero" (while gcc will list the
00057  *       symbol static_assert_failed, making the error message more readable).
00058  *       If the supplied expression can not be evaluated at compile time, Keil will report
00059  *       "error: #28: expression must have a constant value".
00060  *
00061  * @note The macro is intentionally implemented not using do while(0), allowing it to be used
00062  *       outside function blocks (e.g. close to global type- and variable declarations).
00063  *       If used in a code block, it must be used before any executable code in this block.
00064  *
00065  * @param[in]   EXPR   Constant expression to be verified.
00066  */
00067 
00068 #define STATIC_ASSERT(EXPR) typedef char static_assert_failed[(EXPR) ? 1 : -1]
00069 
00070 /**@brief type for holding an encoded (i.e. little endian) 16 bit unsigned integer. */
00071 typedef uint8_t uint16_le_t[2];
00072 
00073 /**@brief type for holding an encoded (i.e. little endian) 32 bit unsigned integer. */
00074 typedef uint8_t uint32_le_t[4];
00075 
00076 /**@brief Byte array type. */
00077 typedef struct
00078 {
00079     uint16_t  size;                 /**< Number of array entries. */
00080     uint8_t * p_data;               /**< Pointer to array entries. */
00081 } uint8_array_t;
00082 
00083 /**@brief Macro for entering a critical region.
00084  *
00085  * @note Due to implementation details, there must exist one and only one call to
00086  *       CRITICAL_REGION_EXIT() for each call to CRITICAL_REGION_ENTER(), and they must be located
00087  *       in the same scope.
00088  */
00089 #define CRITICAL_REGION_ENTER()                                                             \
00090     {                                                                                       \
00091         uint8_t IS_NESTED_CRITICAL_REGION = 0;                                              \
00092         uint32_t CURRENT_INT_PRI = current_int_priority_get();                              \
00093         if (CURRENT_INT_PRI != APP_IRQ_PRIORITY_HIGH)                                       \
00094         {                                                                                   \
00095             uint32_t ERR_CODE = sd_nvic_critical_region_enter(&IS_NESTED_CRITICAL_REGION);  \
00096             if (ERR_CODE == NRF_ERROR_SOFTDEVICE_NOT_ENABLED)                               \
00097             {                                                                               \
00098                 __disable_irq();                                                            \
00099             }                                                                               \
00100             else                                                                            \
00101             {                                                                               \
00102                 APP_ERROR_CHECK(ERR_CODE);                                                  \
00103             }                                                                               \
00104         }        
00105     
00106 /**@brief Macro for leaving a critical region.
00107  *
00108  * @note Due to implementation details, there must exist one and only one call to
00109  *       CRITICAL_REGION_EXIT() for each call to CRITICAL_REGION_ENTER(), and they must be located
00110  *       in the same scope.
00111  */
00112 #define CRITICAL_REGION_EXIT()                                                              \
00113         if (CURRENT_INT_PRI != APP_IRQ_PRIORITY_HIGH)                                       \
00114         {                                                                                   \
00115             uint32_t ERR_CODE;                                                              \
00116             __enable_irq();                                                                 \
00117             ERR_CODE = sd_nvic_critical_region_exit(IS_NESTED_CRITICAL_REGION);             \
00118             if (ERR_CODE != NRF_ERROR_SOFTDEVICE_NOT_ENABLED)                               \
00119             {                                                                               \
00120                 APP_ERROR_CHECK(ERR_CODE);                                                  \
00121             }                                                                               \
00122         }                                                                                   \
00123     }
00124     
00125 /**@brief Perform rounded integer division (as opposed to truncating the result).
00126  *
00127  * @param[in]   A   Numerator.
00128  * @param[in]   B   Denominator.
00129  *
00130  * @return      Rounded (integer) result of dividing A by B.
00131  */
00132 #define ROUNDED_DIV(A, B) (((A) + ((B) / 2)) / (B))
00133 
00134 /**@brief Check if the integer provided is a power of two.
00135  *
00136  * @param[in]   A   Number to be tested.
00137  *
00138  * @return      true if value is power of two.
00139  * @return      false if value not power of two.
00140  */
00141 #define IS_POWER_OF_TWO(A) ( ((A) != 0) && ((((A) - 1) & (A)) == 0) )
00142 
00143 /**@brief To convert ticks to millisecond
00144  * @param[in] time          Number of millseconds that needs to be converted.
00145  * @param[in] resolution    Units to be converted.
00146  */
00147 #define MSEC_TO_UNITS(TIME, RESOLUTION) (((TIME) * 1000) / (RESOLUTION))
00148 
00149 
00150 /**@brief Perform integer division, making sure the result is rounded up.
00151  *
00152  * @details One typical use for this is to compute the number of objects with size B is needed to
00153  *          hold A number of bytes.
00154  *
00155  * @param[in]   A   Numerator.
00156  * @param[in]   B   Denominator.
00157  *
00158  * @return      Integer result of dividing A by B, rounded up.
00159  */
00160 #define CEIL_DIV(A, B)      \
00161     /*lint -save -e573 */   \
00162     ((((A) - 1) / (B)) + 1) \
00163     /*lint -restore */
00164 
00165 /**@brief Function for encoding a uint16 value.
00166  *
00167  * @param[in]   value            Value to be encoded.
00168  * @param[out]  p_encoded_data   Buffer where the encoded data is to be written.
00169  *
00170  * @return      Number of bytes written.
00171  */
00172 static __INLINE uint8_t uint16_encode(uint16_t value, uint8_t * p_encoded_data)
00173 {
00174     p_encoded_data[0] = (uint8_t) ((value & 0x00FF) >> 0);
00175     p_encoded_data[1] = (uint8_t) ((value & 0xFF00) >> 8);
00176     return sizeof(uint16_t);
00177 }
00178     
00179 /**@brief Function for encoding a uint32 value.
00180  *
00181  * @param[in]   value            Value to be encoded.
00182  * @param[out]  p_encoded_data   Buffer where the encoded data is to be written.
00183  *
00184  * @return      Number of bytes written.
00185  */
00186 static __INLINE uint8_t uint32_encode(uint32_t value, uint8_t * p_encoded_data)
00187 {
00188     p_encoded_data[0] = (uint8_t) ((value & 0x000000FF) >> 0);
00189     p_encoded_data[1] = (uint8_t) ((value & 0x0000FF00) >> 8);
00190     p_encoded_data[2] = (uint8_t) ((value & 0x00FF0000) >> 16);
00191     p_encoded_data[3] = (uint8_t) ((value & 0xFF000000) >> 24);
00192     return sizeof(uint32_t);
00193 }
00194 
00195 /**@brief Function for decoding a uint16 value.
00196  *
00197  * @param[in]   p_encoded_data   Buffer where the encoded data is stored.
00198  *
00199  * @return      Decoded value.
00200  */
00201 static __INLINE uint16_t uint16_decode(const uint8_t * p_encoded_data)
00202 {
00203         return ( (((uint16_t)((uint8_t *)p_encoded_data)[0])) | 
00204                  (((uint16_t)((uint8_t *)p_encoded_data)[1]) << 8 ));
00205 }
00206 
00207 /**@brief Function for decoding a uint32 value.
00208  *
00209  * @param[in]   p_encoded_data   Buffer where the encoded data is stored.
00210  *
00211  * @return      Decoded value.
00212  */
00213 static __INLINE uint32_t uint32_decode(const uint8_t * p_encoded_data)
00214 {
00215     return ( (((uint32_t)((uint8_t *)p_encoded_data)[0]) << 0)  |
00216              (((uint32_t)((uint8_t *)p_encoded_data)[1]) << 8)  |
00217              (((uint32_t)((uint8_t *)p_encoded_data)[2]) << 16) |
00218              (((uint32_t)((uint8_t *)p_encoded_data)[3]) << 24 ));
00219 }
00220 
00221     
00222 /**@brief Function for finding the current interrupt level.
00223  *
00224  * @return   Current interrupt level.
00225  * @retval   APP_IRQ_PRIORITY_HIGH    We are running in Application High interrupt level.
00226  * @retval   APP_IRQ_PRIORITY_LOW     We are running in Application Low interrupt level.
00227  * @retval   APP_IRQ_PRIORITY_THREAD  We are running in Thread Mode.
00228  */
00229 static __INLINE uint8_t current_int_priority_get(void)
00230 {
00231     uint32_t isr_vector_num = (SCB->ICSR & SCB_ICSR_VECTACTIVE_Msk);
00232     if (isr_vector_num > 0)
00233     {
00234         int32_t irq_type = ((int32_t)isr_vector_num - EXTERNAL_INT_VECTOR_OFFSET);
00235         return (NVIC_GetPriority((IRQn_Type)irq_type) & 0xFF);
00236     }
00237     else
00238     {
00239         return NRF_APP_PRIORITY_THREAD;
00240     }
00241 }
00242 
00243 /** @brief Function for converting the input voltage (in milli volts) into percentage of 3.0 Volts.
00244  *
00245  *  @details The calculation is based on a linearized version of the battery's discharge
00246  *           curve. 3.0V returns 100% battery level. The limit for power failure is 2.1V and
00247  *           is considered to be the lower boundary.
00248  *
00249  *           The discharge curve for CR2032 is non-linear. In this model it is split into
00250  *           4 linear sections:
00251  *           - Section 1: 3.0V - 2.9V = 100% - 42% (58% drop on 100 mV)
00252  *           - Section 2: 2.9V - 2.74V = 42% - 18% (24% drop on 160 mV)
00253  *           - Section 3: 2.74V - 2.44V = 18% - 6% (12% drop on 300 mV)
00254  *           - Section 4: 2.44V - 2.1V = 6% - 0% (6% drop on 340 mV)
00255  *
00256  *           These numbers are by no means accurate. Temperature and
00257  *           load in the actual application is not accounted for!
00258  *
00259  *  @param[in] mvolts The voltage in mV
00260  *
00261  *  @return    Battery level in percent.
00262 */
00263 static __INLINE uint8_t battery_level_in_percent(const uint16_t mvolts)
00264 {
00265     uint8_t battery_level;
00266 
00267     if (mvolts >= 3000)
00268     {
00269         battery_level = 100;
00270     }
00271     else if (mvolts > 2900)
00272     {
00273         battery_level = 100 - ((3000 - mvolts) * 58) / 100;
00274     }
00275     else if (mvolts > 2740)
00276     {
00277         battery_level = 42 - ((2900 - mvolts) * 24) / 160;
00278     }
00279     else if (mvolts > 2440)
00280     {
00281         battery_level = 18 - ((2740 - mvolts) * 12) / 300;
00282     }
00283     else if (mvolts > 2100)
00284     {
00285         battery_level = 6 - ((2440 - mvolts) * 6) / 340;
00286     }
00287     else
00288     {
00289         battery_level = 0;
00290     }
00291 
00292     return battery_level;
00293 }
00294 
00295 /**@brief Function for checking if a pointer value is aligned to a 4 byte boundary.
00296  *
00297  * @param[in]   p   Pointer value to be checked.
00298  *
00299  * @return      TRUE if pointer is aligned to a 4 byte boundary, FALSE otherwise.
00300  */
00301 static __INLINE bool is_word_aligned(void * p)
00302 {
00303     return (((uint32_t)p & 0x00000003) == 0);
00304 }
00305 
00306 #endif // APP_UTIL_H__
00307 
00308 /** @} */