lib/main/STM32H7/Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_iwdg.c

   1 /**
   2   ******************************************************************************
   3   * @file    stm32h7xx_hal_iwdg.c
   4   * @author  MCD Application Team
   5   * @brief   IWDG HAL module driver.
   6   *          This file provides firmware functions to manage the following
   7   *          functionalities of the Independent Watchdog (IWDG) peripheral:
   8   *           + Initialization and Start functions
   9   *           + IO operation functions
  10   *
  11   @verbatim
  12   ==============================================================================
  13                     ##### IWDG Generic features #####
  14   ==============================================================================
  15   [..]
  16     (+) The IWDG can be started by either software or hardware (configurable
  17         through option byte).
  18
  19     (+) The IWDG is clocked by the Low-Speed Internal clock (LSI) and thus stays
  20         active even if the main clock fails.
  21
  22     (+) Once the IWDG is started, the LSI is forced ON and both cannot be
  23         disabled. The counter starts counting down from the reset value (0xFFF).
  24         When it reaches the end of count value (0x000) a reset signal is
  25         generated (IWDG reset).
  26
  27     (+) Whenever the key value 0x0000 AAAA is written in the IWDG_KR register,
  28         the IWDG_RLR value is reloaded into the counter and the watchdog reset
  29         is prevented.
  30
  31     (+) The IWDG is implemented in the VDD voltage domain that is still functional
  32         in STOP and STANDBY mode (IWDG reset can wake up the CPU from STANDBY).
  33         IWDGRST flag in RCC_CSR register can be used to inform when an IWDG
  34         reset occurs.
  35
  36     (+) Debug mode: When the microcontroller enters debug mode (core halted),
  37         the IWDG counter either continues to work normally or stops, depending
  38         on DBG_IWDG_STOP configuration bit in DBG module, accessible through
  39         __HAL_DBGMCU_FREEZE_IWDG1() or __HAL_DBGMCU_FREEZE2_IWDG2() and
  40         __HAL_DBGMCU_UnFreeze_IWDG1 or __HAL_DBGMCU_UnFreeze2_IWDG2() macros.
  41
  42     [..] Min-max timeout value @32KHz (LSI): ~125us / ~32.7s
  43          The IWDG timeout may vary due to LSI clock frequency dispersion.
  44          STM32H7xx devices provide the capability to measure the LSI clock
  45          frequency (LSI clock is internally connected to TIM16 CH1 input capture).
  46          The measured value can be used to have an IWDG timeout with an
  47          acceptable accuracy.
  48
  49     [..] Default timeout value (necessary for IWDG_SR status register update):
  50          Constant LSI_VALUE is defined based on the nominal LSI clock frequency.
  51          This frequency being subject to variations as mentioned above, the
  52          default timeout value (defined through constant HAL_IWDG_DEFAULT_TIMEOUT
  53          below) may become too short or too long.
  54          In such cases, this default timeout value can be tuned by redefining
  55          the constant LSI_VALUE at user-application level (based, for instance,
  56          on the measured LSI clock frequency as explained above).
  57
  58                      ##### How to use this driver #####
  59   ==============================================================================
  60   [..]
  61     (#) Use IWDG using HAL_IWDG_Init() function to :
  62       (++) Enable instance by writing Start keyword in IWDG_KEY register. LSI
  63            clock is forced ON and IWDG counter starts counting down.
  64       (++) Enable write access to configuration registers:
  65           IWDG_PR, IWDG_RLR and IWDG_WINR.
  66       (++) Configure the IWDG prescaler and counter reload value. This reload
  67            value will be loaded in the IWDG counter each time the watchdog is
  68            reloaded, then the IWDG will start counting down from this value.
  69       (++) Wait for status flags to be reset.
  70       (++) Depending on window parameter:
  71         (+++) If Window Init parameter is same as Window register value,
  72              nothing more is done but reload counter value in order to exit
  73              function with exact time base.
  74         (+++) Else modify Window register. This will automatically reload
  75              watchdog counter.
  76
  77     (#) Then the application program must refresh the IWDG counter at regular
  78         intervals during normal operation to prevent an MCU reset, using
  79         HAL_IWDG_Refresh() function.
  80
  81      *** IWDG HAL driver macros list ***
  82      ====================================
  83      [..]
  84        Below the list of most used macros in IWDG HAL driver:
  85       (+) __HAL_IWDG_START: Enable the IWDG peripheral
  86       (+) __HAL_IWDG_RELOAD_COUNTER: Reloads IWDG counter with value defined in
  87           the reload register
  88
  89   @endverbatim
  90   ******************************************************************************
  91   * @attention
  92   *
  93   * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
  94   * All rights reserved.</center></h2>
  95   *
  96   * This software component is licensed by ST under BSD 3-Clause license,
  97   * the "License"; You may not use this file except in compliance with the
  98   * License. You may obtain a copy of the License at:
  99   *                        opensource.org/licenses/BSD-3-Clause
 100   *
 101   ******************************************************************************
 102   */
 103
 104 /* Includes ------------------------------------------------------------------*/
 105 #include "stm32h7xx_hal.h"
 106
 107 /** @addtogroup STM32H7xx_HAL_Driver
 108   * @{
 109   */
 110
 111 #ifdef HAL_IWDG_MODULE_ENABLED
 112 /** @addtogroup IWDG
 113   * @brief IWDG HAL module driver.
 114   * @{
 115   */
 116
 117 /* Private typedef -----------------------------------------------------------*/
 118 /* Private define ------------------------------------------------------------*/
 119 /** @defgroup IWDG_Private_Defines IWDG Private Defines
 120   * @{
 121   */
 122 /* Status register needs up to 5 LSI clock periods divided by the clock
 123    prescaler to be updated. The number of LSI clock periods is upper-rounded to
 124    6 for the timeout value calculation.
 125    The timeout value is also calculated using the highest prescaler (256) and
 126    the LSI_VALUE constant. The value of this constant can be changed by the user
 127    to take into account possible LSI clock period variations.
 128    The timeout value is multiplied by 1000 to be converted in milliseconds. */
 129 #define HAL_IWDG_DEFAULT_TIMEOUT ((6UL * 256UL * 1000UL) / LSI_VALUE)
 130 /**
 131   * @}
 132   */
 133
 134 /* Private macro -------------------------------------------------------------*/
 135 /* Private variables ---------------------------------------------------------*/
 136 /* Private function prototypes -----------------------------------------------*/
 137 /* Exported functions --------------------------------------------------------*/
 138
 139 /** @addtogroup IWDG_Exported_Functions
 140   * @{
 141   */
 142
 143 /** @addtogroup IWDG_Exported_Functions_Group1
 144   *  @brief    Initialization and Start functions.
 145   *
 146 @verbatim
 147  ===============================================================================
 148           ##### Initialization and Start functions #####
 149  ===============================================================================
 150  [..]  This section provides functions allowing to:
 151       (+) Initialize the IWDG according to the specified parameters in the
 152           IWDG_InitTypeDef of associated handle.
 153       (+) Manage Window option.
 154       (+) Once initialization is performed in HAL_IWDG_Init function, Watchdog
 155           is reloaded in order to exit function with correct time base.
 156
 157 @endverbatim
 158   * @{
 159   */
 160
 161 /**
 162   * @brief  Initialize the IWDG according to the specified parameters in the
 163   *         IWDG_InitTypeDef and start watchdog. Before exiting function,
 164   *         watchdog is refreshed in order to have correct time base.
 165   * @param  hiwdg  pointer to a IWDG_HandleTypeDef structure that contains
 166   *                the configuration information for the specified IWDG module.
 167   * @retval HAL status
 168   */
 169 HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
 170 {
 171   uint32_t tickstart;
 172
 173   /* Check the IWDG handle allocation */
 174   if (hiwdg == NULL)
 175   {
 176     return HAL_ERROR;
 177   }
 178
 179   /* Check the parameters */
 180   assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
 181   assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
 182   assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
 183   assert_param(IS_IWDG_WINDOW(hiwdg->Init.Window));
 184
 185   /* Enable IWDG. LSI is turned on automatically */
 186   __HAL_IWDG_START(hiwdg);
 187
 188   /* Enable write access to IWDG_PR, IWDG_RLR and IWDG_WINR registers by writing
 189   0x5555 in KR */
 190   IWDG_ENABLE_WRITE_ACCESS(hiwdg);
 191
 192   /* Write to IWDG registers the Prescaler & Reload values to work with */
 193   hiwdg->Instance->PR = hiwdg->Init.Prescaler;
 194   hiwdg->Instance->RLR = hiwdg->Init.Reload;
 195
 196   /* Check pending flag, if previous update not done, return timeout */
 197   tickstart = HAL_GetTick();
 198
 199   /* Wait for register to be updated */
 200   while (hiwdg->Instance->SR != 0x00u)
 201   {
 202     if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
 203     {
 204       return HAL_TIMEOUT;
 205     }
 206   }
 207
 208   /* If window parameter is different than current value, modify window
 209   register */
 210   if (hiwdg->Instance->WINR != hiwdg->Init.Window)
 211   {
 212     /* Write to IWDG WINR the IWDG_Window value to compare with. In any case,
 213     even if window feature is disabled, Watchdog will be reloaded by writing
 214     windows register */
 215     hiwdg->Instance->WINR = hiwdg->Init.Window;
 216   }
 217   else
 218   {
 219     /* Reload IWDG counter with value defined in the reload register */
 220     __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 221   }
 222
 223   /* Return function status */
 224   return HAL_OK;
 225 }
 226
 227 /**
 228   * @}
 229   */
 230
 231
 232 /** @addtogroup IWDG_Exported_Functions_Group2
 233   *  @brief   IO operation functions
 234   *
 235 @verbatim
 236  ===============================================================================
 237                       ##### IO operation functions #####
 238  ===============================================================================
 239  [..]  This section provides functions allowing to:
 240       (+) Refresh the IWDG.
 241
 242 @endverbatim
 243   * @{
 244   */
 245
 246
 247 /**
 248   * @brief  Refresh the IWDG.
 249   * @param  hiwdg  pointer to a IWDG_HandleTypeDef structure that contains
 250   *                the configuration information for the specified IWDG module.
 251   * @retval HAL status
 252   */
 253 HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
 254 {
 255   /* Reload IWDG counter with value defined in the reload register */
 256   __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 257
 258   /* Return function status */
 259   return HAL_OK;
 260 }
 261
 262 /**
 263   * @}
 264   */
 265
 266 /**
 267   * @}
 268   */
 269
 270 #endif /* HAL_IWDG_MODULE_ENABLED */
 271 /**
 272   * @}
 273   */
 274
 275 /**
 276   * @}
 277   */
 278
 279 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/