/** ****************************************************************************** * @file stm32f4xx_iwdg.c * @author MCD Application Team * @version V1.0.0RC1 * @date 25-August-2011 * @brief This file provides firmware functions to manage the following * functionalities of the Independent watchdog (IWDG) peripheral: * - Prescaler and Counter configuration * - IWDG activation * - Flag management * * @verbatim * * =================================================================== * IWDG features * =================================================================== * * The IWDG can be started by either software or hardware (configurable * through option byte). * * The IWDG is clocked by its own dedicated low-speed clock (LSI) and * thus stays active even if the main clock fails. * Once the IWDG is started, the LSI is forced ON and cannot be disabled * (LSI cannot be disabled too), and the counter starts counting down from * the reset value of 0xFFF. When it reaches the end of count value (0x000) * a system reset is generated. * The IWDG counter should be reloaded at regular intervals to prevent * an MCU reset. * * The IWDG is implemented in the VDD voltage domain that is still functional * in STOP and STANDBY mode (IWDG reset can wake-up from STANDBY). * * IWDGRST flag in RCC_CSR register can be used to inform when a IWDG * reset occurs. * * Min-max timeout value @32KHz (LSI): ~125us / ~32.7s * The IWDG timeout may vary due to LSI frequency dispersion. STM32F4xx * devices provide the capability to measure the LSI frequency (LSI clock * connected internally to TIM5 CH4 input capture). The measured value * can be used to have an IWDG timeout with an acceptable accuracy. * For more information, please refer to the STM32F4xx Reference manual * * * =================================================================== * How to use this driver * =================================================================== * 1. Enable write access to IWDG_PR and IWDG_RLR registers using * IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function * * 2. Configure the IWDG prescaler using IWDG_SetPrescaler() function * * 3. Configure the IWDG counter value using IWDG_SetReload() function. * This value will be loaded in the IWDG counter each time the counter * is reloaded, then the IWDG will start counting down from this value. * * 4. Start the IWDG using IWDG_Enable() function, when the IWDG is used * in software mode (no need to enable the LSI, it will be enabled * by hardware) * * 5. Then the application program must reload the IWDG counter at regular * intervals during normal operation to prevent an MCU reset, using * IWDG_ReloadCounter() function. * * @endverbatim * ****************************************************************************** * @attention * * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS. * *

© COPYRIGHT 2011 STMicroelectronics

****************************************************************************** */ /* Includes ------------------------------------------------------------------*/ #include "stm32f4xx_iwdg.h" /** @addtogroup STM32F4xx_StdPeriph_Driver * @{ */ /** @defgroup IWDG * @brief IWDG driver modules * @{ */ /* Private typedef -----------------------------------------------------------*/ /* Private define ------------------------------------------------------------*/ /* KR register bit mask */ #define KR_KEY_RELOAD ((uint16_t)0xAAAA) #define KR_KEY_ENABLE ((uint16_t)0xCCCC) /* Private macro -------------------------------------------------------------*/ /* Private variables ---------------------------------------------------------*/ /* Private function prototypes -----------------------------------------------*/ /* Private functions ---------------------------------------------------------*/ /** @defgroup IWDG_Private_Functions * @{ */ /** @defgroup IWDG_Group1 Prescaler and Counter configuration functions * @brief Prescaler and Counter configuration functions * @verbatim =============================================================================== Prescaler and Counter configuration functions =============================================================================== @endverbatim * @{ */ /** * @brief Enables or disables write access to IWDG_PR and IWDG_RLR registers. * @param IWDG_WriteAccess: new state of write access to IWDG_PR and IWDG_RLR registers. * This parameter can be one of the following values: * @arg IWDG_WriteAccess_Enable: Enable write access to IWDG_PR and IWDG_RLR registers * @arg IWDG_WriteAccess_Disable: Disable write access to IWDG_PR and IWDG_RLR registers * @retval None */ void IWDG_WriteAccessCmd(uint16_t IWDG_WriteAccess) { /* Check the parameters */ assert_param(IS_IWDG_WRITE_ACCESS(IWDG_WriteAccess)); IWDG->KR = IWDG_WriteAccess; } /** * @brief Sets IWDG Prescaler value. * @param IWDG_Prescaler: specifies the IWDG Prescaler value. * This parameter can be one of the following values: * @arg IWDG_Prescaler_4: IWDG prescaler set to 4 * @arg IWDG_Prescaler_8: IWDG prescaler set to 8 * @arg IWDG_Prescaler_16: IWDG prescaler set to 16 * @arg IWDG_Prescaler_32: IWDG prescaler set to 32 * @arg IWDG_Prescaler_64: IWDG prescaler set to 64 * @arg IWDG_Prescaler_128: IWDG prescaler set to 128 * @arg IWDG_Prescaler_256: IWDG prescaler set to 256 * @retval None */ void IWDG_SetPrescaler(uint8_t IWDG_Prescaler) { /* Check the parameters */ assert_param(IS_IWDG_PRESCALER(IWDG_Prescaler)); IWDG->PR = IWDG_Prescaler; } /** * @brief Sets IWDG Reload value. * @param Reload: specifies the IWDG Reload value. * This parameter must be a number between 0 and 0x0FFF. * @retval None */ void IWDG_SetReload(uint16_t Reload) { /* Check the parameters */ assert_param(IS_IWDG_RELOAD(Reload)); IWDG->RLR = Reload; } /** * @brief Reloads IWDG counter with value defined in the reload register * (write access to IWDG_PR and IWDG_RLR registers disabled). * @param None * @retval None */ void IWDG_ReloadCounter(void) { IWDG->KR = KR_KEY_RELOAD; } /** * @} */ /** @defgroup IWDG_Group2 IWDG activation function * @brief IWDG activation function * @verbatim =============================================================================== IWDG activation function =============================================================================== @endverbatim * @{ */ /** * @brief Enables IWDG (write access to IWDG_PR and IWDG_RLR registers disabled). * @param None * @retval None */ void IWDG_Enable(void) { IWDG->KR = KR_KEY_ENABLE; } /** * @} */ /** @defgroup IWDG_Group3 Flag management function * @brief Flag management function * @verbatim =============================================================================== Flag management function =============================================================================== @endverbatim * @{ */ /** * @brief Checks whether the specified IWDG flag is set or not. * @param IWDG_FLAG: specifies the flag to check. * This parameter can be one of the following values: * @arg IWDG_FLAG_PVU: Prescaler Value Update on going * @arg IWDG_FLAG_RVU: Reload Value Update on going * @retval The new state of IWDG_FLAG (SET or RESET). */ FlagStatus IWDG_GetFlagStatus(uint16_t IWDG_FLAG) { FlagStatus bitstatus = RESET; /* Check the parameters */ assert_param(IS_IWDG_FLAG(IWDG_FLAG)); if ((IWDG->SR & IWDG_FLAG) != (uint32_t)RESET) { bitstatus = SET; } else { bitstatus = RESET; } /* Return the flag status */ return bitstatus; } /** * @} */ /** * @} */ /** * @} */ /** * @} */ /******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/