lib/main/STM32F3/Drivers/STM32F30x_StdPeriph_Driver/src/stm32f30x_iwdg.c

   1 /**
   2   ******************************************************************************
   3   * @file    stm32f30x_iwdg.c
   4   * @author  MCD Application Team
   5   * @version V1.1.1
   6   * @date    04-April-2014
   7   * @brief   This file provides firmware functions to manage the following
   8   *          functionalities of the Independent watchdog (IWDG) peripheral:
   9   *           + Prescaler and Counter configuration
  10   *           + IWDG activation
  11   *           + Flag management
  12   *
  13   @verbatim
  14
  15  ===============================================================================
  16                           ##### IWDG features #####
  17  ===============================================================================
  18     [..] The IWDG can be started by either software or hardware (configurable
  19          through option byte).
  20     [..] The IWDG is clocked by its own dedicated low-speed clock (LSI) and
  21          thus stays active even if the main clock fails.
  22          Once the IWDG is started, the LSI is forced ON and cannot be disabled
  23          (LSI cannot be disabled too), and the counter starts counting down from
  24          the reset value of 0xFFF. When it reaches the end of count value (0x000)
  25          a system reset is generated.
  26          The IWDG counter should be reloaded at regular intervals to prevent
  27          an MCU reset.
  28     [..] The IWDG is implemented in the VDD voltage domain that is still functional
  29          in STOP and STANDBY mode (IWDG reset can wake-up from STANDBY).
  30     [..] IWDGRST flag in RCC_CSR register can be used to inform when a IWDG
  31          reset occurs.
  32     [..] Min-max timeout value @41KHz (LSI): ~0.1ms / ~25.5s
  33          The IWDG timeout may vary due to LSI frequency dispersion. STM32F30x
  34          devices provide the capability to measure the LSI frequency (LSI clock
  35          connected internally to TIM16 CH1 input capture). The measured value
  36          can be used to have an IWDG timeout with an acceptable accuracy.
  37          For more information, please refer to the STM32F30x Reference manual.
  38
  39                       ##### How to use this driver #####
  40  ===============================================================================
  41     [..] This driver allows to use IWDG peripheral with either window option enabled
  42          or disabled. To do so follow one of the two procedures below.
  43     (#) Window option is enabled:
  44         (++) Start the IWDG using IWDG_Enable() function, when the IWDG is used
  45              in software mode (no need to enable the LSI, it will be enabled
  46              by hardware).
  47         (++) Enable write access to IWDG_PR and IWDG_RLR registers using
  48              IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function.
  49         (++) Configure the IWDG prescaler using IWDG_SetPrescaler() function.
  50         (++) Configure the IWDG counter value using IWDG_SetReload() function.
  51              This value will be loaded in the IWDG counter each time the counter
  52              is reloaded, then the IWDG will start counting down from this value.
  53         (++) Wait for the IWDG registers to be updated using IWDG_GetFlagStatus() function.
  54         (++) Configure the IWDG refresh window using IWDG_SetWindowValue() function.
  55
  56     (#) Window option is disabled:
  57         (++) Enable write access to IWDG_PR and IWDG_RLR registers using
  58              IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function.
  59         (++) Configure the IWDG prescaler using IWDG_SetPrescaler() function.
  60         (++) Configure the IWDG counter value using IWDG_SetReload() function.
  61              This value will be loaded in the IWDG counter each time the counter
  62              is reloaded, then the IWDG will start counting down from this value.
  63         (++) Wait for the IWDG registers to be updated using IWDG_GetFlagStatus() function.
  64         (++) reload the IWDG counter at regular intervals during normal operation
  65              to prevent an MCU reset, using IWDG_ReloadCounter() function.
  66         (++) Start the IWDG using IWDG_Enable() function, when the IWDG is used
  67              in software mode (no need to enable the LSI, it will be enabled
  68              by hardware).
  69
  70   @endverbatim
  71
  72   ******************************************************************************
  73   * @attention
  74   *
  75   * <h2><center>&copy; COPYRIGHT 2014 STMicroelectronics</center></h2>
  76   *
  77   * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  78   * You may not use this file except in compliance with the License.
  79   * You may obtain a copy of the License at:
  80   *
  81   *        http://www.st.com/software_license_agreement_liberty_v2
  82   *
  83   * Unless required by applicable law or agreed to in writing, software
  84   * distributed under the License is distributed on an "AS IS" BASIS,
  85   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  86   * See the License for the specific language governing permissions and
  87   * limitations under the License.
  88   *
  89   ******************************************************************************
  90   */
  91
  92 /* Includes ------------------------------------------------------------------*/
  93 #include "stm32f30x_iwdg.h"
  94
  95 /** @addtogroup STM32F30x_StdPeriph_Driver
  96   * @{
  97   */
  98
  99 /** @defgroup IWDG
 100   * @brief IWDG driver modules
 101   * @{
 102   */
 103
 104 /* Private typedef -----------------------------------------------------------*/
 105 /* Private define ------------------------------------------------------------*/
 106 /* ---------------------- IWDG registers bit mask ----------------------------*/
 107 /* KR register bit mask */
 108 #define KR_KEY_RELOAD    ((uint16_t)0xAAAA)
 109 #define KR_KEY_ENABLE    ((uint16_t)0xCCCC)
 110
 111 /* Private macro -------------------------------------------------------------*/
 112 /* Private variables ---------------------------------------------------------*/
 113 /* Private function prototypes -----------------------------------------------*/
 114 /* Private functions ---------------------------------------------------------*/
 115
 116 /** @defgroup IWDG_Private_Functions
 117   * @{
 118   */
 119
 120 /** @defgroup IWDG_Group1 Prescaler and Counter configuration functions
 121  *  @brief   Prescaler and Counter configuration functions
 122  *
 123 @verbatim
 124  ===============================================================================
 125             ##### Prescaler and Counter configuration functions #####
 126  ===============================================================================
 127
 128 @endverbatim
 129   * @{
 130   */
 131
 132 /**
 133   * @brief  Enables or disables write access to IWDG_PR and IWDG_RLR registers.
 134   * @param  IWDG_WriteAccess: new state of write access to IWDG_PR and IWDG_RLR registers.
 135   *   This parameter can be one of the following values:
 136   *     @arg IWDG_WriteAccess_Enable: Enable write access to IWDG_PR and IWDG_RLR registers
 137   *     @arg IWDG_WriteAccess_Disable: Disable write access to IWDG_PR and IWDG_RLR registers
 138   * @retval None
 139   */
 140 void IWDG_WriteAccessCmd(uint16_t IWDG_WriteAccess)
 141 {
 142   /* Check the parameters */
 143   assert_param(IS_IWDG_WRITE_ACCESS(IWDG_WriteAccess));
 144   IWDG->KR = IWDG_WriteAccess;
 145 }
 146
 147 /**
 148   * @brief  Sets IWDG Prescaler value.
 149   * @param  IWDG_Prescaler: specifies the IWDG Prescaler value.
 150   *   This parameter can be one of the following values:
 151   *     @arg IWDG_Prescaler_4: IWDG prescaler set to 4
 152   *     @arg IWDG_Prescaler_8: IWDG prescaler set to 8
 153   *     @arg IWDG_Prescaler_16: IWDG prescaler set to 16
 154   *     @arg IWDG_Prescaler_32: IWDG prescaler set to 32
 155   *     @arg IWDG_Prescaler_64: IWDG prescaler set to 64
 156   *     @arg IWDG_Prescaler_128: IWDG prescaler set to 128
 157   *     @arg IWDG_Prescaler_256: IWDG prescaler set to 256
 158   * @retval None
 159   */
 160 void IWDG_SetPrescaler(uint8_t IWDG_Prescaler)
 161 {
 162   /* Check the parameters */
 163   assert_param(IS_IWDG_PRESCALER(IWDG_Prescaler));
 164   IWDG->PR = IWDG_Prescaler;
 165 }
 166
 167 /**
 168   * @brief  Sets IWDG Reload value.
 169   * @param  Reload: specifies the IWDG Reload value.
 170   *   This parameter must be a number between 0 and 0x0FFF.
 171   * @retval None
 172   */
 173 void IWDG_SetReload(uint16_t Reload)
 174 {
 175   /* Check the parameters */
 176   assert_param(IS_IWDG_RELOAD(Reload));
 177   IWDG->RLR = Reload;
 178 }
 179
 180 /**
 181   * @brief  Reloads IWDG counter with value defined in the reload register
 182   *   (write access to IWDG_PR and IWDG_RLR registers disabled).
 183   * @param  None
 184   * @retval None
 185   */
 186 void IWDG_ReloadCounter(void)
 187 {
 188   IWDG->KR = KR_KEY_RELOAD;
 189 }
 190
 191
 192 /**
 193   * @brief  Sets the IWDG window value.
 194   * @param  WindowValue: specifies the window value to be compared to the downcounter.
 195   * @retval None
 196   */
 197 void IWDG_SetWindowValue(uint16_t WindowValue)
 198 {
 199   /* Check the parameters */
 200   assert_param(IS_IWDG_WINDOW_VALUE(WindowValue));
 201   IWDG->WINR = WindowValue;
 202 }
 203
 204 /**
 205   * @}
 206   */
 207
 208 /** @defgroup IWDG_Group2 IWDG activation function
 209  *  @brief   IWDG activation function
 210  *
 211 @verbatim
 212  ===============================================================================
 213                     ##### IWDG activation function #####
 214  ===============================================================================
 215
 216 @endverbatim
 217   * @{
 218   */
 219
 220 /**
 221   * @brief  Enables IWDG (write access to IWDG_PR and IWDG_RLR registers disabled).
 222   * @param  None
 223   * @retval None
 224   */
 225 void IWDG_Enable(void)
 226 {
 227   IWDG->KR = KR_KEY_ENABLE;
 228 }
 229
 230 /**
 231   * @}
 232   */
 233
 234 /** @defgroup IWDG_Group3 Flag management function
 235  *  @brief  Flag management function
 236  *
 237 @verbatim
 238  ===============================================================================
 239                      ##### Flag management function #####
 240  ===============================================================================
 241
 242 @endverbatim
 243   * @{
 244   */
 245
 246 /**
 247   * @brief  Checks whether the specified IWDG flag is set or not.
 248   * @param  IWDG_FLAG: specifies the flag to check.
 249   *   This parameter can be one of the following values:
 250   *     @arg IWDG_FLAG_PVU: Prescaler Value Update on going
 251   *     @arg IWDG_FLAG_RVU: Reload Value Update on going
 252   *     @arg IWDG_FLAG_WVU: Counter Window Value Update on going
 253   * @retval The new state of IWDG_FLAG (SET or RESET).
 254   */
 255 FlagStatus IWDG_GetFlagStatus(uint16_t IWDG_FLAG)
 256 {
 257   FlagStatus bitstatus = RESET;
 258   /* Check the parameters */
 259   assert_param(IS_IWDG_FLAG(IWDG_FLAG));
 260   if ((IWDG->SR & IWDG_FLAG) != (uint32_t)RESET)
 261   {
 262     bitstatus = SET;
 263   }
 264   else
 265   {
 266     bitstatus = RESET;
 267   }
 268   /* Return the flag status */
 269   return bitstatus;
 270 }
 271
 272 /**
 273   * @}
 274   */
 275
 276 /**
 277   * @}
 278   */
 279
 280 /**
 281   * @}
 282   */
 283
 284 /**
 285   * @}
 286   */
 287
 288 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/