1 /**
2 ******************************************************************************
3 * @file stm32f0xx_wwdg.c
4 * @author MCD Application Team
5 * @version V1.5.0
6 * @date 05-December-2014
7 * @brief This file provides firmware functions to manage the following
8 * functionalities of the Window watchdog (WWDG) peripheral:
9 * + Prescaler, Refresh window and Counter configuration
10 * + WWDG activation
11 * + Interrupts and flags management
12 *
13 * @verbatim
14 *
15 ==============================================================================
16 ##### WWDG features #####
17 ==============================================================================
18 [..] Once enabled the WWDG generates a system reset on expiry of a programmed
19 time period, unless the program refreshes the counter (downcounter)
20 before to reach 0x3F value (i.e. a reset is generated when the counter
21 value rolls over from 0x40 to 0x3F).
22 [..] An MCU reset is also generated if the counter value is refreshed
23 before the counter has reached the refresh window value. This
24 implies that the counter must be refreshed in a limited window.
25
26 [..] Once enabled the WWDG cannot be disabled except by a system reset.
27
28 [..] WWDGRST flag in RCC_CSR register can be used to inform when a WWDG
29 reset occurs.
30
31 [..] The WWDG counter input clock is derived from the APB clock divided
32 by a programmable prescaler.
33
34 [..] WWDG counter clock = PCLK1 / Prescaler.
35 [..] WWDG timeout = (WWDG counter clock) * (counter value).
36
37 [..] Min-max timeout value @32MHz (PCLK1): ~85us / ~43ms.
38
39 ##### How to use this driver #####
40 ==============================================================================
41 [..]
42 (#) Enable WWDG clock using RCC_APB1PeriphClockCmd(RCC_APB1Periph_WWDG, ENABLE)
43 function.
44
45 (#) Configure the WWDG prescaler using WWDG_SetPrescaler() function.
46
47 (#) Configure the WWDG refresh window using WWDG_SetWindowValue() function.
48
49 (#) Set the WWDG counter value and start it using WWDG_Enable() function.
50 When the WWDG is enabled the counter value should be configured to
51 a value greater than 0x40 to prevent generating an immediate reset.
52
53 (#) Optionally you can enable the Early wakeup interrupt which is
54 generated when the counter reach 0x40.
55 Once enabled this interrupt cannot be disabled except by a system reset.
56
57 (#) Then the application program must refresh the WWDG counter at regular
58 intervals during normal operation to prevent an MCU reset, using
59 WWDG_SetCounter() function. This operation must occur only when
60 the counter value is lower than the refresh window value,
61 programmed using WWDG_SetWindowValue().
62
63 * @endverbatim
64 *
65 ******************************************************************************
66 * @attention
67 *
68 * <h2><center>© COPYRIGHT 2014 STMicroelectronics</center></h2>
69 *
70 * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
71 * You may not use this file except in compliance with the License.
72 * You may obtain a copy of the License at:
73 *
74 * http://www.st.com/software_license_agreement_liberty_v2
75 *
76 * Unless required by applicable law or agreed to in writing, software
77 * distributed under the License is distributed on an "AS IS" BASIS,
78 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
79 * See the License for the specific language governing permissions and
80 * limitations under the License.
81 *
82 ******************************************************************************
83 */
84
85 /* Includes ------------------------------------------------------------------*/
86 #include "stm32f0xx_wwdg.h"
87 #include "stm32f0xx_rcc.h"
88
89 /** @addtogroup STM32F0xx_StdPeriph_Driver
90 * @{
91 */
92
93 /** @defgroup WWDG
94 * @brief WWDG driver modules
95 * @{
96 */
97
98 /* Private typedef -----------------------------------------------------------*/
99 /* Private define ------------------------------------------------------------*/
100 /* --------------------- WWDG registers bit mask ---------------------------- */
101 /* CFR register bit mask */
102 #define CFR_WDGTB_MASK ((uint32_t)0xFFFFFE7F)
103 #define CFR_W_MASK ((uint32_t)0xFFFFFF80)
104 #define BIT_MASK ((uint8_t)0x7F)
105
106 /* Private macro -------------------------------------------------------------*/
107 /* Private variables ---------------------------------------------------------*/
108 /* Private function prototypes -----------------------------------------------*/
109 /* Private functions ---------------------------------------------------------*/
110
111 /** @defgroup WWDG_Private_Functions
112 * @{
113 */
114
115 /** @defgroup WWDG_Group1 Prescaler, Refresh window and Counter configuration functions
116 * @brief Prescaler, Refresh window and Counter configuration functions
117 *
118 @verbatim
119 ==============================================================================
120 ##### Prescaler, Refresh window and Counter configuration functions #####
121 ==============================================================================
122
123 @endverbatim
124 * @{
125 */
126
127 /**
128 * @brief Deinitializes the WWDG peripheral registers to their default reset values.
129 * @param None
130 * @retval None
131 */
WWDG_DeInit(void)132 void WWDG_DeInit(void)
133 {
134 RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, ENABLE);
135 RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, DISABLE);
136 }
137
138 /**
139 * @brief Sets the WWDG Prescaler.
140 * @param WWDG_Prescaler: specifies the WWDG Prescaler.
141 * This parameter can be one of the following values:
142 * @arg WWDG_Prescaler_1: WWDG counter clock = (PCLK1/4096)/1
143 * @arg WWDG_Prescaler_2: WWDG counter clock = (PCLK1/4096)/2
144 * @arg WWDG_Prescaler_4: WWDG counter clock = (PCLK1/4096)/4
145 * @arg WWDG_Prescaler_8: WWDG counter clock = (PCLK1/4096)/8
146 * @retval None
147 */
WWDG_SetPrescaler(uint32_t WWDG_Prescaler)148 void WWDG_SetPrescaler(uint32_t WWDG_Prescaler)
149 {
150 uint32_t tmpreg = 0;
151 /* Check the parameters */
152 assert_param(IS_WWDG_PRESCALER(WWDG_Prescaler));
153 /* Clear WDGTB[1:0] bits */
154 tmpreg = WWDG->CFR & CFR_WDGTB_MASK;
155 /* Set WDGTB[1:0] bits according to WWDG_Prescaler value */
156 tmpreg |= WWDG_Prescaler;
157 /* Store the new value */
158 WWDG->CFR = tmpreg;
159 }
160
161 /**
162 * @brief Sets the WWDG window value.
163 * @param WindowValue: specifies the window value to be compared to the downcounter.
164 * This parameter value must be lower than 0x80.
165 * @retval None
166 */
WWDG_SetWindowValue(uint8_t WindowValue)167 void WWDG_SetWindowValue(uint8_t WindowValue)
168 {
169 __IO uint32_t tmpreg = 0;
170
171 /* Check the parameters */
172 assert_param(IS_WWDG_WINDOW_VALUE(WindowValue));
173 /* Clear W[6:0] bits */
174
175 tmpreg = WWDG->CFR & CFR_W_MASK;
176
177 /* Set W[6:0] bits according to WindowValue value */
178 tmpreg |= WindowValue & (uint32_t) BIT_MASK;
179
180 /* Store the new value */
181 WWDG->CFR = tmpreg;
182 }
183
184 /**
185 * @brief Enables the WWDG Early Wakeup interrupt(EWI).
186 * @note Once enabled this interrupt cannot be disabled except by a system reset.
187 * @param None
188 * @retval None
189 */
WWDG_EnableIT(void)190 void WWDG_EnableIT(void)
191 {
192 WWDG->CFR |= WWDG_CFR_EWI;
193 }
194
195 /**
196 * @brief Sets the WWDG counter value.
197 * @param Counter: specifies the watchdog counter value.
198 * This parameter must be a number between 0x40 and 0x7F (to prevent
199 * generating an immediate reset).
200 * @retval None
201 */
WWDG_SetCounter(uint8_t Counter)202 void WWDG_SetCounter(uint8_t Counter)
203 {
204 /* Check the parameters */
205 assert_param(IS_WWDG_COUNTER(Counter));
206 /* Write to T[6:0] bits to configure the counter value, no need to do
207 a read-modify-write; writing a 0 to WDGA bit does nothing */
208 WWDG->CR = Counter & BIT_MASK;
209 }
210
211 /**
212 * @}
213 */
214
215 /** @defgroup WWDG_Group2 WWDG activation functions
216 * @brief WWDG activation functions
217 *
218 @verbatim
219 ==============================================================================
220 ##### WWDG activation function #####
221 ==============================================================================
222
223 @endverbatim
224 * @{
225 */
226
227 /**
228 * @brief Enables WWDG and load the counter value.
229 * @param Counter: specifies the watchdog counter value.
230 * This parameter must be a number between 0x40 and 0x7F (to prevent
231 * generating an immediate reset).
232 * @retval None
233 */
WWDG_Enable(uint8_t Counter)234 void WWDG_Enable(uint8_t Counter)
235 {
236 /* Check the parameters */
237 assert_param(IS_WWDG_COUNTER(Counter));
238 WWDG->CR = WWDG_CR_WDGA | Counter;
239 }
240
241 /**
242 * @}
243 */
244
245 /** @defgroup WWDG_Group3 Interrupts and flags management functions
246 * @brief Interrupts and flags management functions
247 *
248 @verbatim
249 ==============================================================================
250 ##### Interrupts and flags management functions #####
251 ==============================================================================
252
253 @endverbatim
254 * @{
255 */
256
257 /**
258 * @brief Checks whether the Early Wakeup interrupt flag is set or not.
259 * @param None
260 * @retval The new state of the Early Wakeup interrupt flag (SET or RESET).
261 */
WWDG_GetFlagStatus(void)262 FlagStatus WWDG_GetFlagStatus(void)
263 {
264 FlagStatus bitstatus = RESET;
265
266 if ((WWDG->SR) != (uint32_t)RESET)
267 {
268 bitstatus = SET;
269 }
270 else
271 {
272 bitstatus = RESET;
273 }
274 return bitstatus;
275 }
276
277 /**
278 * @brief Clears Early Wakeup interrupt flag.
279 * @param None
280 * @retval None
281 */
WWDG_ClearFlag(void)282 void WWDG_ClearFlag(void)
283 {
284 WWDG->SR = (uint32_t)RESET;
285 }
286
287 /**
288 * @}
289 */
290
291 /**
292 * @}
293 */
294
295 /**
296 * @}
297 */
298
299 /**
300 * @}
301 */
302
303 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
304