mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
targets/cmsis/TARGET_STM/TARGET_DISCO_F051R8/stm32f0xx_iwdg.c
- Committer:
- shaoziyang
- Date:
- 2014-09-13
- Revision:
- 323:9e901b0a5aa1
- Parent:
- 130:1dec54e4aec3
File content as of revision 323:9e901b0a5aa1:
/** ****************************************************************************** * @file stm32f0xx_iwdg.c * @author MCD Application Team * @version V1.3.0 * @date 16-January-2014 * @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 @40KHz (LSI): ~0.1ms / ~28.3s The IWDG timeout may vary due to LSI frequency dispersion. STM32F0xx devices provide the capability to measure the LSI frequency (LSI clock should be seleted as RTC clock which is internally connected to TIM10 CH1 input capture). The measured value can be used to have an IWDG timeout with an acceptable accuracy. For more information, please refer to the STM32F0xx Reference manual. ##### How to use this driver ##### ============================================================================== [..] This driver allows to use IWDG peripheral with either window option enabled or disabled. To do so follow one of the two procedures below. (#) Window option is enabled: (++) 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). (++) Enable write access to IWDG_PR and IWDG_RLR registers using IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function. (++) Configure the IWDG prescaler using IWDG_SetPrescaler() function. (++) 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. (++) Wait for the IWDG registers to be updated using IWDG_GetFlagStatus() function. (++) Configure the IWDG refresh window using IWDG_SetWindowValue() function. (#) Window option is disabled: (++) Enable write access to IWDG_PR and IWDG_RLR registers using IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function. (++) Configure the IWDG prescaler using IWDG_SetPrescaler() function. (++) 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. (++) Wait for the IWDG registers to be updated using IWDG_GetFlagStatus() function. (++) reload the IWDG counter at regular intervals during normal operation to prevent an MCU reset, using IWDG_ReloadCounter() function. (++) 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). @endverbatim * ****************************************************************************** * @attention * * <h2><center>© COPYRIGHT(c) 2014 STMicroelectronics</center></h2> * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. Neither the name of STMicroelectronics nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************** */ /* Includes ------------------------------------------------------------------*/ #include "stm32f0xx_iwdg.h" /** @addtogroup STM32F0xx_StdPeriph_Driver * @{ */ /** @defgroup IWDG * @brief IWDG driver modules * @{ */ /* Private typedef -----------------------------------------------------------*/ /* Private define ------------------------------------------------------------*/ /* ---------------------- IWDG registers bit mask ----------------------------*/ /* 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; } /** * @brief Sets the IWDG window value. * @param WindowValue: specifies the window value to be compared to the downcounter. * @retval None */ void IWDG_SetWindowValue(uint16_t WindowValue) { /* Check the parameters */ assert_param(IS_IWDG_WINDOW_VALUE(WindowValue)); IWDG->WINR = WindowValue; } /** * @} */ /** @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 * @arg IWDG_FLAG_WVU: Counter Window 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 STMicroelectronics *****END OF FILE****/