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 Low-Speed clock (LSI) and thus stays active even
  20         if the main clock fails.
  21
  22     (+) Once the IWDG is started, the LSI is forced ON and both can not 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 in the counter and the watchdog reset is
  29         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 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 frequency dispersion. STM32H7xx
  44          devices provide the capability to measure the LSI frequency (LSI clock
  45          connected internally to TIM16 CH1 input capture). The measured value
  46          can be used to have an IWDG timeout with an acceptable accuracy.
  47
  48                      ##### How to use this driver #####
  49   ==============================================================================
  50   [..]
  51     (#) Use IWDG using HAL_IWDG_Init() function to :
  52       (++) Enable instance by writing Start keyword in IWDG_KEY register. LSI
  53            clock is forced ON and IWDG counter starts counting down.
  54       (++) Enable write access to configuration registers:
  55           IWDG_PR, IWDG_RLR and IWDG_WINR.
  56       (++) Configure the IWDG prescaler and counter reload value. This reload
  57            value will be loaded in the IWDG counter each time the watchdog is
  58            reloaded, then the IWDG will start counting down from this value.
  59       (++) Wait for status flags to be reset.
  60       (++) Depending on window parameter:
  61         (+++) If Window Init parameter is same as Window register value,
  62              nothing more is done but reload counter value in order to exit
  63              function with exact time base.
  64         (+++) Else modify Window register. This will automatically reload
  65              watchdog counter.
  66
  67     (#) Then the application program must refresh the IWDG counter at regular
  68         intervals during normal operation to prevent an MCU reset, using
  69         HAL_IWDG_Refresh() function.
  70
  71      *** IWDG HAL driver macros list ***
  72      ====================================
  73      [..]
  74        Below the list of most used macros in IWDG HAL driver:
  75       (+) __HAL_IWDG_START: Enable the IWDG peripheral
  76       (+) __HAL_IWDG_RELOAD_COUNTER: Reloads IWDG counter with value defined in
  77           the reload register
  78
  79   @endverbatim
  80   ******************************************************************************
  81   * @attention
  82   *
  83   * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
  84   * All rights reserved.</center></h2>
  85   *
  86   * This software component is licensed by ST under BSD 3-Clause license,
  87   * the "License"; You may not use this file except in compliance with the
  88   * License. You may obtain a copy of the License at:
  89   *                        opensource.org/licenses/BSD-3-Clause
  90   *
  91   ******************************************************************************
  92   */
  93
  94 /* Includes ------------------------------------------------------------------*/
  95 #include "stm32h7xx_hal.h"
  96
  97 /** @addtogroup STM32H7xx_HAL_Driver
  98   * @{
  99   */
 100
 101 #ifdef HAL_IWDG_MODULE_ENABLED
 102 /** @addtogroup IWDG
 103   * @brief IWDG HAL module driver.
 104   * @{
 105   */
 106
 107 /* Private typedef -----------------------------------------------------------*/
 108 /* Private define ------------------------------------------------------------*/
 109 /** @defgroup IWDG_Private_Defines IWDG Private Defines
 110   * @{
 111   */
 112 /* Status register need 5 RC LSI divided by prescaler clock to be updated. With
 113    higher prescaler (256), and according to LSI variation, we need to wait at
 114    least 6 cycles so 48 ms. */
 115 #define HAL_IWDG_DEFAULT_TIMEOUT            48u
 116 /**
 117   * @}
 118   */
 119
 120 /* Private macro -------------------------------------------------------------*/
 121 /* Private variables ---------------------------------------------------------*/
 122 /* Private function prototypes -----------------------------------------------*/
 123 /* Exported functions --------------------------------------------------------*/
 124
 125 /** @addtogroup IWDG_Exported_Functions
 126   * @{
 127   */
 128
 129 /** @addtogroup IWDG_Exported_Functions_Group1
 130   *  @brief    Initialization and Start functions.
 131   *
 132 @verbatim
 133  ===============================================================================
 134           ##### Initialization and Start functions #####
 135  ===============================================================================
 136  [..]  This section provides functions allowing to:
 137       (+) Initialize the IWDG according to the specified parameters in the
 138           IWDG_InitTypeDef of associated handle.
 139       (+) Manage Window option.
 140       (+) Once initialization is performed in HAL_IWDG_Init function, Watchdog
 141           is reloaded in order to exit function with correct time base.
 142
 143 @endverbatim
 144   * @{
 145   */
 146
 147 /**
 148   * @brief  Initialize the IWDG according to the specified parameters in the
 149   *         IWDG_InitTypeDef and start watchdog. Before exiting function,
 150   *         watchdog is refreshed in order to have correct time base.
 151   * @param  hiwdg  pointer to a IWDG_HandleTypeDef structure that contains
 152   *                the configuration information for the specified IWDG module.
 153   * @retval HAL status
 154   */
 155 HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
 156 {
 157   uint32_t tickstart;
 158
 159   /* Check the IWDG handle allocation */
 160   if (hiwdg == NULL)
 161   {
 162     return HAL_ERROR;
 163   }
 164
 165   /* Check the parameters */
 166   assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
 167   assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
 168   assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
 169   assert_param(IS_IWDG_WINDOW(hiwdg->Init.Window));
 170
 171   /* Enable IWDG. LSI is turned on automatically */
 172   __HAL_IWDG_START(hiwdg);
 173
 174   /* Enable write access to IWDG_PR, IWDG_RLR and IWDG_WINR registers by writing
 175   0x5555 in KR */
 176   IWDG_ENABLE_WRITE_ACCESS(hiwdg);
 177
 178   /* Write to IWDG registers the Prescaler & Reload values to work with */
 179   hiwdg->Instance->PR = hiwdg->Init.Prescaler;
 180   hiwdg->Instance->RLR = hiwdg->Init.Reload;
 181
 182   /* Check pending flag, if previous update not done, return timeout */
 183   tickstart = HAL_GetTick();
 184
 185   /* Wait for register to be updated */
 186   while (hiwdg->Instance->SR != 0x00u)
 187   {
 188     if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
 189     {
 190       return HAL_TIMEOUT;
 191     }
 192   }
 193
 194   /* If window parameter is different than current value, modify window
 195   register */
 196   if (hiwdg->Instance->WINR != hiwdg->Init.Window)
 197   {
 198     /* Write to IWDG WINR the IWDG_Window value to compare with. In any case,
 199     even if window feature is disabled, Watchdog will be reloaded by writing
 200     windows register */
 201     hiwdg->Instance->WINR = hiwdg->Init.Window;
 202   }
 203   else
 204   {
 205     /* Reload IWDG counter with value defined in the reload register */
 206     __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 207   }
 208
 209   /* Return function status */
 210   return HAL_OK;
 211 }
 212
 213 /**
 214   * @}
 215   */
 216
 217
 218 /** @addtogroup IWDG_Exported_Functions_Group2
 219   *  @brief   IO operation functions
 220   *
 221 @verbatim
 222  ===============================================================================
 223                       ##### IO operation functions #####
 224  ===============================================================================
 225  [..]  This section provides functions allowing to:
 226       (+) Refresh the IWDG.
 227
 228 @endverbatim
 229   * @{
 230   */
 231
 232
 233 /**
 234   * @brief  Refresh the IWDG.
 235   * @param  hiwdg  pointer to a IWDG_HandleTypeDef structure that contains
 236   *                the configuration information for the specified IWDG module.
 237   * @retval HAL status
 238   */
 239 HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
 240 {
 241   /* Reload IWDG counter with value defined in the reload register */
 242   __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 243
 244   /* Return function status */
 245   return HAL_OK;
 246 }
 247
 248 /**
 249   * @}
 250   */
 251
 252 /**
 253   * @}
 254   */
 255
 256 #endif /* HAL_IWDG_MODULE_ENABLED */
 257 /**
 258   * @}
 259   */
 260
 261 /**
 262   * @}
 263   */
 264
 265 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/