stm32l4xx_hal_wwdg.c

00001 /**
00002   ******************************************************************************
00003   * @file    stm32l4xx_hal_wwdg.c
00004   * @author  MCD Application Team
00005   * @version V1.5.1
00006   * @date    31-May-2016
00007   * @brief   WWDG HAL module driver.
00008   *          This file provides firmware functions to manage the following 
00009   *          functionalities of the Window Watchdog (WWDG) peripheral:
00010   *           + Initialization and Configuration function
00011   *           + IO operation functions
00012   @verbatim
00013   ==============================================================================
00014                       ##### WWDG specific features #####
00015   ==============================================================================
00016   [..]
00017     Once enabled the WWDG generates a system reset on expiry of a programmed
00018     time period, unless the program refreshes the counter (T[6;0] downcounter)
00019     before reaching 0x3F value (i.e. a reset is generated when the counter
00020     value rolls over from 0x40 to 0x3F).
00021 
00022     (+) An MCU reset is also generated if the counter value is refreshed
00023         before the counter has reached the refresh window value. This
00024         implies that the counter must be refreshed in a limited window.
00025 
00026     (+) Once enabled the WWDG cannot be disabled except by a system reset.
00027 
00028     (+) WWDGRST flag in RCC_CSR register informs when a WWDG reset has 
00029         occurred (check available with __HAL_RCC_GET_FLAG(RCC_FLAG_WWDGRST)).
00030 
00031     (+) The WWDG downcounter input clock is derived from the APB clock divided
00032         by a programmable prescaler.
00033 
00034     (+) WWDG downcounter clock (Hz) = PCLK1 / (4096 * Prescaler)
00035 
00036     (+) WWDG timeout (ms) = (1000 * (T[5;0] + 1)) / (WWDG downcounter clock)
00037         where T[5;0] are the lowest 6 bits of downcounter.
00038 
00039     (+) WWDG Counter refresh is allowed between the following limits :
00040         (++) min time (ms) = (1000 * (T[5;0] - Window)) / (WWDG downcounter clock)
00041         (++) max time (ms) = (1000 * (T[5;0] - 0x40)) / (WWDG downcounter clock)
00042 
00043     (+) Min-max timeout value @80 MHz(PCLK1): ~51.2 us / ~26.22 ms
00044 
00045     (+) The Early Wakeup Interrupt (EWI) can be used if specific safety 
00046         operations or data logging must be performed before the actual reset is
00047         generated. When the downcounter reaches the value 0x40, an EWI interrupt
00048         is generated and the corresponding interrupt service routine (ISR) can 
00049         be used to trigger specific actions (such as communications or data 
00050         logging), before resetting the device.
00051         In some applications, the EWI interrupt can be used to manage a software
00052         system check and/or system recovery/graceful degradation, without 
00053         generating a WWDG reset. In this case, the corresponding interrupt 
00054         service routine (ISR) should reload the WWDG counter to avoid the WWDG 
00055         reset, then trigger the required actions.
00056         Note:When the EWI interrupt cannot be served, e.g. due to a system lock 
00057         in a higher priority task, the WWDG reset will eventually be generated.
00058 
00059     (+) Debug mode : When the microcontroller enters debug mode (core halted),
00060         the WWDG counter either continues to work normally or stops, depending 
00061         on DBG_WWDG_STOP configuration bit in DBG module, accessible through
00062         __HAL_DBGMCU_FREEZE_WWDG() and __HAL_DBGMCU_UNFREEZE_WWDG() macros
00063 
00064                      ##### How to use this driver #####
00065   ==============================================================================
00066   [..]
00067     (+) Enable WWDG APB1 clock using __HAL_RCC_WWDG_CLK_ENABLE().
00068 
00069     (+) Set the WWDG prescaler, refresh window, counter value and Early Wakeup 
00070         Interrupt mode using using HAL_WWDG_Init() function.
00071         This enables WWDG peripheral and the downcounter starts downcounting 
00072         from given counter value.
00073         Init function can be called again to modify all watchdog parameters, 
00074         however if EWI mode has been set once, it can't be clear until next 
00075         reset.
00076 
00077     (+) The application program must refresh the WWDG counter at regular
00078         intervals during normal operation to prevent an MCU reset using
00079         HAL_WWDG_Refresh() function. This operation must occur only when
00080         the counter is lower than the window value already programmed.
00081 
00082     (+) if Early Wakeup Interrupt mode is enable an interrupt is generated when 
00083         the counter reaches 0x40. User can add his own code in weak function 
00084         HAL_WWDG_EarlyWakeupCallback().
00085 
00086      *** WWDG HAL driver macros list ***
00087      ==================================
00088      [..]
00089        Below the list of most used macros in WWDG HAL driver.
00090 
00091       (+) __HAL_WWDG_GET_IT_SOURCE: Check the selected WWDG's interrupt source.
00092       (+) __HAL_WWDG_GET_FLAG: Get the selected WWDG's flag status.
00093       (+) __HAL_WWDG_CLEAR_FLAG: Clear the WWDG's pending flags.
00094 
00095   @endverbatim
00096   ******************************************************************************
00097   * @attention
00098   *
00099   * <h2><center>&copy; COPYRIGHT(c) 2016 STMicroelectronics</center></h2>
00100   *
00101   * Redistribution and use in source and binary forms, with or without modification,
00102   * are permitted provided that the following conditions are met:
00103   *   1. Redistributions of source code must retain the above copyright notice,
00104   *      this list of conditions and the following disclaimer.
00105   *   2. Redistributions in binary form must reproduce the above copyright notice,
00106   *      this list of conditions and the following disclaimer in the documentation
00107   *      and/or other materials provided with the distribution.
00108   *   3. Neither the name of STMicroelectronics nor the names of its contributors
00109   *      may be used to endorse or promote products derived from this software
00110   *      without specific prior written permission.
00111   *
00112   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00113   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00114   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00115   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
00116   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00117   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
00118   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00119   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
00120   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
00121   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00122   *
00123   ******************************************************************************
00124   */
00125 
00126 /* Includes ------------------------------------------------------------------*/
00127 #include "stm32l4xx_hal.h"
00128 
00129 /** @addtogroup STM32L4xx_HAL_Driver
00130   * @{
00131   */
00132 
00133 #ifdef HAL_WWDG_MODULE_ENABLED
00134 /** @defgroup WWDG WWDG
00135   * @brief WWDG HAL module driver.
00136   * @{
00137   */
00138 
00139 /* Private typedef -----------------------------------------------------------*/
00140 /* Private define ------------------------------------------------------------*/
00141 /* Private macro -------------------------------------------------------------*/
00142 /* Private variables ---------------------------------------------------------*/
00143 /* Private function prototypes -----------------------------------------------*/
00144 /* Exported functions --------------------------------------------------------*/
00145 
00146 /** @defgroup WWDG_Exported_Functions WWDG Exported Functions
00147   * @{
00148   */
00149 
00150 /** @defgroup WWDG_Exported_Functions_Group1 Initialization and Configuration functions
00151  *  @brief    Initialization and Configuration functions.
00152  *
00153 @verbatim
00154   ==============================================================================
00155           ##### Initialization and Configuration functions #####
00156   ==============================================================================
00157   [..]  
00158     This section provides functions allowing to:
00159       (+) Initialize and start the WWDG according to the specified parameters
00160           in the WWDG_InitTypeDef of associated handle.
00161       (+) Initialize the WWDG MSP.
00162 
00163 @endverbatim
00164   * @{
00165   */
00166 
00167 /**
00168   * @brief  Initialize the WWDG according to the specified.
00169   *         parameters in the WWDG_InitTypeDef of  associated handle.
00170   * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
00171   *                the configuration information for the specified WWDG module.
00172   * @retval HAL status
00173   */
00174 HAL_StatusTypeDef HAL_WWDG_Init(WWDG_HandleTypeDef *hwwdg)
00175 {
00176   /* Check the WWDG handle allocation */
00177   if(hwwdg == NULL)
00178   {
00179     return HAL_ERROR;
00180   }
00181 
00182   /* Check the parameters */
00183   assert_param(IS_WWDG_ALL_INSTANCE(hwwdg->Instance));
00184   assert_param(IS_WWDG_PRESCALER(hwwdg->Init.Prescaler));
00185   assert_param(IS_WWDG_WINDOW(hwwdg->Init.Window));
00186   assert_param(IS_WWDG_COUNTER(hwwdg->Init.Counter));
00187   assert_param(IS_WWDG_EWI_MODE(hwwdg->Init.EWIMode));
00188 
00189   /* Init the low level hardware */
00190   HAL_WWDG_MspInit(hwwdg);
00191 
00192   /* Set WWDG Counter */
00193   WRITE_REG(hwwdg->Instance->CR, (WWDG_CR_WDGA | hwwdg->Init.Counter));
00194 
00195   /* Set WWDG Prescaler and Window */
00196   WRITE_REG(hwwdg->Instance->CFR, (hwwdg->Init.EWIMode | hwwdg->Init.Prescaler | hwwdg->Init.Window));
00197 
00198   /* Return function status */
00199   return HAL_OK;
00200 }
00201 
00202 
00203 /**
00204   * @brief  Initialize the WWDG MSP.
00205   * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
00206   *                the configuration information for the specified WWDG module.
00207   * @note   When rewriting this function in user file, mechanism may be added
00208   *         to avoid multiple initialize when HAL_WWDG_Init function is called
00209   *         again to change parameters.
00210   * @retval None
00211   */
00212 __weak void HAL_WWDG_MspInit(WWDG_HandleTypeDef *hwwdg)
00213 {
00214   /* Prevent unused argument(s) compilation warning */
00215   UNUSED(hwwdg);
00216 
00217   /* NOTE: This function should not be modified, when the callback is needed,
00218            the HAL_WWDG_MspInit could be implemented in the user file
00219    */
00220 }
00221 
00222 /**
00223   * @}
00224   */
00225 
00226 /** @defgroup WWDG_Exported_Functions_Group2 IO operation functions
00227  *  @brief    IO operation functions 
00228  *
00229 @verbatim
00230   ==============================================================================
00231                       ##### IO operation functions #####
00232   ==============================================================================  
00233   [..]
00234     This section provides functions allowing to:
00235     (+) Refresh the WWDG.
00236     (+) Handle WWDG interrupt request and associated function callback.
00237 
00238 @endverbatim
00239   * @{
00240   */
00241 
00242 /**
00243   * @brief  Refresh the WWDG.
00244   * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
00245   *                the configuration information for the specified WWDG module.
00246   * @retval HAL status
00247   */
00248 HAL_StatusTypeDef HAL_WWDG_Refresh(WWDG_HandleTypeDef *hwwdg)
00249 {
00250   /* Write to WWDG CR the WWDG Counter value to refresh with */
00251   WRITE_REG(hwwdg->Instance->CR, (hwwdg->Init.Counter));
00252 
00253   /* Return function status */
00254   return HAL_OK;
00255 }
00256 
00257 /**
00258   * @brief  Handle WWDG interrupt request.
00259   * @note   The Early Wakeup Interrupt (EWI) can be used if specific safety operations
00260   *         or data logging must be performed before the actual reset is generated.
00261   *         The EWI interrupt is enabled by calling HAL_WWDG_Init function with 
00262   *         EWIMode set to WWDG_EWI_ENABLE.
00263   *         When the downcounter reaches the value 0x40, and EWI interrupt is
00264   *         generated and the corresponding Interrupt Service Routine (ISR) can
00265   *         be used to trigger specific actions (such as communications or data
00266   *         logging), before resetting the device.
00267   * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
00268   *                the configuration information for the specified WWDG module.
00269   * @retval None
00270   */
00271 void HAL_WWDG_IRQHandler(WWDG_HandleTypeDef *hwwdg)
00272 {
00273   /* Check if Early Wakeup Interrupt is enable */
00274   if(__HAL_WWDG_GET_IT_SOURCE(hwwdg, WWDG_IT_EWI) != RESET)
00275   {
00276     /* Check if WWDG Early Wakeup Interrupt occurred */
00277     if(__HAL_WWDG_GET_FLAG(hwwdg, WWDG_FLAG_EWIF) != RESET)
00278     {
00279       /* Clear the WWDG Early Wakeup flag */
00280       __HAL_WWDG_CLEAR_FLAG(hwwdg, WWDG_FLAG_EWIF);
00281 
00282       /* Early Wakeup callback */ 
00283       HAL_WWDG_EarlyWakeupCallback(hwwdg);
00284     }
00285   }
00286 }
00287 
00288 
00289 /**
00290   * @brief  WWDG Early Wakeup callback.
00291   * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
00292   *                the configuration information for the specified WWDG module.
00293   * @retval None
00294   */
00295 __weak void HAL_WWDG_EarlyWakeupCallback(WWDG_HandleTypeDef* hwwdg)
00296 {
00297   /* Prevent unused argument(s) compilation warning */
00298   UNUSED(hwwdg);
00299 
00300   /* NOTE: This function should not be modified, when the callback is needed,
00301            the HAL_WWDG_EarlyWakeupCallback could be implemented in the user file
00302    */
00303 }
00304 
00305 /**
00306   * @}
00307   */
00308 
00309 /**
00310   * @}
00311   */
00312 
00313 #endif /* HAL_WWDG_MODULE_ENABLED */
00314 /**
00315   * @}
00316   */
00317 
00318 /**
00319   * @}
00320   */
00321 
00322 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/