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/**
******************************************************************************
* @file stm32f30x_wwdg.c
* @author MCD Application Team
* @version V1.1.0
* @date 27-February-2014
* @brief This file provides firmware functions to manage the following
* functionalities of the Window watchdog (WWDG) peripheral:
* + Prescaler, Refresh window and Counter configuration
* + WWDG activation
* + Interrupts and flags management
*
* @verbatim
*
==============================================================================
##### WWDG features #####
==============================================================================
[..] Once enabled the WWDG generates a system reset on expiry of a programmed
time period, unless the program refreshes the counter (downcounter)
before to reach 0x3F value (i.e. a reset is generated when the counter
value rolls over from 0x40 to 0x3F).
[..] An MCU reset is also generated if the counter value is refreshed
before the counter has reached the refresh window value. This
implies that the counter must be refreshed in a limited window.
[..] Once enabled the WWDG cannot be disabled except by a system reset.
[..] WWDGRST flag in RCC_CSR register can be used to inform when a WWDG
reset occurs.
[..] The WWDG counter input clock is derived from the APB clock divided
by a programmable prescaler.
[..] WWDG counter clock = PCLK1 / Prescaler.
[..] WWDG timeout = (WWDG counter clock) * (counter value).
[..] Min-max timeout value @36MHz (PCLK1): ~114us / ~58.3ms.
##### How to use this driver #####
==============================================================================
[..]
(#) Enable WWDG clock using RCC_APB1PeriphClockCmd(RCC_APB1Periph_WWDG, ENABLE)
function.
(#) Configure the WWDG prescaler using WWDG_SetPrescaler() function.
(#) Configure the WWDG refresh window using WWDG_SetWindowValue() function.
(#) Set the WWDG counter value and start it using WWDG_Enable() function.
When the WWDG is enabled the counter value should be configured to
a value greater than 0x40 to prevent generating an immediate reset.
(#) Optionally you can enable the Early wakeup interrupt which is
generated when the counter reach 0x40.
Once enabled this interrupt cannot be disabled except by a system reset.
(#) Then the application program must refresh the WWDG counter at regular
intervals during normal operation to prevent an MCU reset, using
WWDG_SetCounter() function. This operation must occur only when
the counter value is lower than the refresh window value,
programmed using WWDG_SetWindowValue().
@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 "stm32f30x_wwdg.h"
#include "stm32f30x_rcc.h"
/** @addtogroup STM32F30x_StdPeriph_Driver
* @{
*/
/** @defgroup WWDG
* @brief WWDG driver modules
* @{
*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* --------------------- WWDG registers bit mask ---------------------------- */
/* CFR register bit mask */
#define CFR_WDGTB_MASK ((uint32_t)0xFFFFFE7F)
#define CFR_W_MASK ((uint32_t)0xFFFFFF80)
#define BIT_MASK ((uint8_t)0x7F)
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
/** @defgroup WWDG_Private_Functions
* @{
*/
/** @defgroup WWDG_Group1 Prescaler, Refresh window and Counter configuration functions
* @brief Prescaler, Refresh window and Counter configuration functions
*
@verbatim
==============================================================================
##### Prescaler, Refresh window and Counter configuration functions #####
==============================================================================
@endverbatim
* @{
*/
/**
* @brief Deinitializes the WWDG peripheral registers to their default reset values.
* @param None
* @retval None
*/
void WWDG_DeInit(void)
{
RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, ENABLE);
RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, DISABLE);
}
/**
* @brief Sets the WWDG Prescaler.
* @param WWDG_Prescaler: specifies the WWDG Prescaler.
* This parameter can be one of the following values:
* @arg WWDG_Prescaler_1: WWDG counter clock = (PCLK1/4096)/1
* @arg WWDG_Prescaler_2: WWDG counter clock = (PCLK1/4096)/2
* @arg WWDG_Prescaler_4: WWDG counter clock = (PCLK1/4096)/4
* @arg WWDG_Prescaler_8: WWDG counter clock = (PCLK1/4096)/8
* @retval None
*/
void WWDG_SetPrescaler(uint32_t WWDG_Prescaler)
{
uint32_t tmpreg = 0;
/* Check the parameters */
assert_param(IS_WWDG_PRESCALER(WWDG_Prescaler));
/* Clear WDGTB[1:0] bits */
tmpreg = WWDG->CFR & CFR_WDGTB_MASK;
/* Set WDGTB[1:0] bits according to WWDG_Prescaler value */
tmpreg |= WWDG_Prescaler;
/* Store the new value */
WWDG->CFR = tmpreg;
}
/**
* @brief Sets the WWDG window value.
* @param WindowValue: specifies the window value to be compared to the downcounter.
* This parameter value must be lower than 0x80.
* @retval None
*/
void WWDG_SetWindowValue(uint8_t WindowValue)
{
__IO uint32_t tmpreg = 0;
/* Check the parameters */
assert_param(IS_WWDG_WINDOW_VALUE(WindowValue));
/* Clear W[6:0] bits */
tmpreg = WWDG->CFR & CFR_W_MASK;
/* Set W[6:0] bits according to WindowValue value */
tmpreg |= WindowValue & (uint32_t) BIT_MASK;
/* Store the new value */
WWDG->CFR = tmpreg;
}
/**
* @brief Enables the WWDG Early Wakeup interrupt(EWI).
* @note Once enabled this interrupt cannot be disabled except by a system reset.
* @param None
* @retval None
*/
void WWDG_EnableIT(void)
{
WWDG->CFR |= WWDG_CFR_EWI;
}
/**
* @brief Sets the WWDG counter value.
* @param Counter: specifies the watchdog counter value.
* This parameter must be a number between 0x40 and 0x7F (to prevent generating
* an immediate reset).
* @retval None
*/
void WWDG_SetCounter(uint8_t Counter)
{
/* Check the parameters */
assert_param(IS_WWDG_COUNTER(Counter));
/* Write to T[6:0] bits to configure the counter value, no need to do
a read-modify-write; writing a 0 to WDGA bit does nothing */
WWDG->CR = Counter & BIT_MASK;
}
/**
* @}
*/
/** @defgroup WWDG_Group2 WWDG activation functions
* @brief WWDG activation functions
*
@verbatim
==============================================================================
##### WWDG activation function #####
==============================================================================
@endverbatim
* @{
*/
/**
* @brief Enables WWDG and load the counter value.
* @param Counter: specifies the watchdog counter value.
* This parameter must be a number between 0x40 and 0x7F (to prevent generating
* an immediate reset).
* @retval None
*/
void WWDG_Enable(uint8_t Counter)
{
/* Check the parameters */
assert_param(IS_WWDG_COUNTER(Counter));
WWDG->CR = WWDG_CR_WDGA | Counter;
}
/**
* @}
*/
/** @defgroup WWDG_Group3 Interrupts and flags management functions
* @brief Interrupts and flags management functions
*
@verbatim
==============================================================================
##### Interrupts and flags management functions #####
==============================================================================
@endverbatim
* @{
*/
/**
* @brief Checks whether the Early Wakeup interrupt flag is set or not.
* @param None
* @retval The new state of the Early Wakeup interrupt flag (SET or RESET).
*/
FlagStatus WWDG_GetFlagStatus(void)
{
FlagStatus bitstatus = RESET;
if ((WWDG->SR) != (uint32_t)RESET)
{
bitstatus = SET;
}
else
{
bitstatus = RESET;
}
return bitstatus;
}
/**
* @brief Clears Early Wakeup interrupt flag.
* @param None
* @retval None
*/
void WWDG_ClearFlag(void)
{
WWDG->SR = (uint32_t)RESET;
}
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
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