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