lib/main/STM32F7/Drivers/STM32F7xx_HAL_Driver/Src/stm32f7xx_hal_iwdg.c

   1 /**
   2   ******************************************************************************
   3   * @file    stm32f7xx_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_IWDG() and __HAL_DBGMCU_UNFREEZE_IWDG() macros.
  40
  41     [..] Min-max timeout value @32KHz (LSI): ~125us / ~32.7s
  42          The IWDG timeout may vary due to LSI frequency dispersion. STM32F7xx
  43          devices provide the capability to measure the LSI frequency (LSI clock
  44          connected internally to TIM16 CH1 input capture). The measured value
  45          can be used to have an IWDG timeout with an acceptable accuracy.
  46
  47                      ##### How to use this driver #####
  48   ==============================================================================
  49   [..]
  50     (#) Use IWDG using HAL_IWDG_Init() function to :
  51       (+) Enable instance by writing Start keyword in IWDG_KEY register. LSI
  52            clock is forced ON and IWDG counter starts counting down.
  53       (+) Enable write access to configuration registers:
  54           IWDG_PR, IWDG_RLR and IWDG_WINR.
  55       (+) Configure the IWDG prescaler and counter reload value. This reload
  56            value will be loaded in the IWDG counter each time the watchdog is
  57            reloaded, then the IWDG will start counting down from this value.
  58       (+) Wait for status flags to be reset.
  59       (+) Depending on window parameter:
  60         (++) If Window Init parameter is same as Window register value,
  61              nothing more is done but reload counter value in order to exit
  62              function with exact time base.
  63         (++) Else modify Window register. This will automatically reload
  64              watchdog counter.
  65
  66     (#) Then the application program must refresh the IWDG counter at regular
  67         intervals during normal operation to prevent an MCU reset, using
  68         HAL_IWDG_Refresh() function.
  69
  70      *** IWDG HAL driver macros list ***
  71      ====================================
  72      [..]
  73        Below the list of most used macros in IWDG HAL driver:
  74       (+) __HAL_IWDG_START: Enable the IWDG peripheral
  75       (+) __HAL_IWDG_RELOAD_COUNTER: Reloads IWDG counter with value defined in
  76           the reload register
  77
  78   @endverbatim
  79   ******************************************************************************
  80   * @attention
  81   *
  82   * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
  83   * All rights reserved.</center></h2>
  84   *
  85   * This software component is licensed by ST under BSD 3-Clause license,
  86   * the "License"; You may not use this file except in compliance with the
  87   * License. You may obtain a copy of the License at:
  88   *                        opensource.org/licenses/BSD-3-Clause
  89   *
  90   ******************************************************************************
  91   */
  92
  93 /* Includes ------------------------------------------------------------------*/
  94 #include "stm32f7xx_hal.h"
  95
  96 /** @addtogroup STM32F7xx_HAL_Driver
  97   * @{
  98   */
  99
 100 #ifdef HAL_IWDG_MODULE_ENABLED
 101 /** @addtogroup IWDG
 102   * @brief IWDG HAL module driver.
 103   * @{
 104   */
 105
 106 /* Private typedef -----------------------------------------------------------*/
 107 /* Private define ------------------------------------------------------------*/
 108 /** @defgroup IWDG_Private_Defines IWDG Private Defines
 109   * @{
 110   */
 111 /* Status register need 5 RC LSI divided by prescaler clock to be updated. With
 112    higher prescaler (256), and according to LSI variation, we need to wait at
 113    least 6 cycles so 48 ms. */
 114 #define HAL_IWDG_DEFAULT_TIMEOUT            48u
 115 /**
 116   * @}
 117   */
 118
 119 /* Private macro -------------------------------------------------------------*/
 120 /* Private variables ---------------------------------------------------------*/
 121 /* Private function prototypes -----------------------------------------------*/
 122 /* Exported functions --------------------------------------------------------*/
 123
 124 /** @addtogroup IWDG_Exported_Functions
 125   * @{
 126   */
 127
 128 /** @addtogroup IWDG_Exported_Functions_Group1
 129  *  @brief    Initialization and Start functions.
 130  *
 131 @verbatim
 132  ===============================================================================
 133           ##### Initialization and Start functions #####
 134  ===============================================================================
 135  [..]  This section provides functions allowing to:
 136       (+) Initialize the IWDG according to the specified parameters in the
 137           IWDG_InitTypeDef of associated handle.
 138       (+) Manage Window option.
 139       (+) Once initialization is performed in HAL_IWDG_Init function, Watchdog
 140           is reloaded in order to exit function with correct time base.
 141
 142 @endverbatim
 143   * @{
 144   */
 145
 146 /**
 147   * @brief  Initialize the IWDG according to the specified parameters in the
 148   *         IWDG_InitTypeDef and start watchdog. Before exiting function,
 149   *         watchdog is refreshed in order to have correct time base.
 150   * @param  hiwdg  pointer to a IWDG_HandleTypeDef structure that contains
 151   *                the configuration information for the specified IWDG module.
 152   * @retval HAL status
 153   */
 154 HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
 155 {
 156   uint32_t tickstart;
 157
 158   /* Check the IWDG handle allocation */
 159   if (hiwdg == NULL)
 160   {
 161     return HAL_ERROR;
 162   }
 163
 164   /* Check the parameters */
 165   assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
 166   assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
 167   assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
 168   assert_param(IS_IWDG_WINDOW(hiwdg->Init.Window));
 169
 170   /* Enable IWDG. LSI is turned on automatically */
 171   __HAL_IWDG_START(hiwdg);
 172
 173   /* Enable write access to IWDG_PR, IWDG_RLR and IWDG_WINR registers by writing
 174   0x5555 in KR */
 175   IWDG_ENABLE_WRITE_ACCESS(hiwdg);
 176
 177   /* Write to IWDG registers the Prescaler & Reload values to work with */
 178   hiwdg->Instance->PR = hiwdg->Init.Prescaler;
 179   hiwdg->Instance->RLR = hiwdg->Init.Reload;
 180
 181   /* Check pending flag, if previous update not done, return timeout */
 182   tickstart = HAL_GetTick();
 183
 184   /* Wait for register to be updated */
 185   while (hiwdg->Instance->SR != 0x00u)
 186   {
 187     if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
 188     {
 189       return HAL_TIMEOUT;
 190     }
 191   }
 192
 193   /* If window parameter is different than current value, modify window
 194   register */
 195   if (hiwdg->Instance->WINR != hiwdg->Init.Window)
 196   {
 197     /* Write to IWDG WINR the IWDG_Window value to compare with. In any case,
 198     even if window feature is disabled, Watchdog will be reloaded by writing
 199     windows register */
 200     hiwdg->Instance->WINR = hiwdg->Init.Window;
 201   }
 202   else
 203   {
 204     /* Reload IWDG counter with value defined in the reload register */
 205     __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 206   }
 207
 208   /* Return function status */
 209   return HAL_OK;
 210 }
 211
 212 /**
 213   * @}
 214   */
 215
 216
 217 /** @addtogroup IWDG_Exported_Functions_Group2
 218  *  @brief   IO operation functions
 219  *
 220 @verbatim
 221  ===============================================================================
 222                       ##### IO operation functions #####
 223  ===============================================================================
 224  [..]  This section provides functions allowing to:
 225       (+) Refresh the IWDG.
 226
 227 @endverbatim
 228   * @{
 229   */
 230
 231
 232 /**
 233   * @brief  Refresh the IWDG.
 234   * @param  hiwdg  pointer to a IWDG_HandleTypeDef structure that contains
 235   *                the configuration information for the specified IWDG module.
 236   * @retval HAL status
 237   */
 238 HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
 239 {
 240   /* Reload IWDG counter with value defined in the reload register */
 241   __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 242
 243   /* Return function status */
 244   return HAL_OK;
 245 }
 246
 247 /**
 248   * @}
 249   */
 250
 251 /**
 252   * @}
 253   */
 254
 255 #endif /* HAL_IWDG_MODULE_ENABLED */
 256 /**
 257   * @}
 258   */
 259
 260 /**
 261   * @}
 262   */
 263
 264 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/