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STM32F0xx Standard Peripherals Firmware Library
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STM32F0xx_StdPeriph_Examples/RTC/RTC_LSI/main.c
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00001 /** 00002 ****************************************************************************** 00003 * @file RTC/RTC_LSI/main.c 00004 * @author MCD Application Team 00005 * @version V1.4.0 00006 * @date 24-July-2014 00007 * @brief Main program body 00008 ****************************************************************************** 00009 * @attention 00010 * 00011 * <h2><center>© COPYRIGHT 2014 STMicroelectronics</center></h2> 00012 * 00013 * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License"); 00014 * You may not use this file except in compliance with the License. 00015 * You may obtain a copy of the License at: 00016 * 00017 * http://www.st.com/software_license_agreement_liberty_v2 00018 * 00019 * Unless required by applicable law or agreed to in writing, software 00020 * distributed under the License is distributed on an "AS IS" BASIS, 00021 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00022 * See the License for the specific language governing permissions and 00023 * limitations under the License. 00024 * 00025 ****************************************************************************** 00026 */ 00027 00028 /* Includes ------------------------------------------------------------------*/ 00029 #include "main.h" 00030 00031 /** @addtogroup STM32F0xx_StdPeriph_Examples 00032 * @{ 00033 */ 00034 00035 /** @addtogroup RTC_LSI 00036 * @{ 00037 */ 00038 00039 /* Private typedef -----------------------------------------------------------*/ 00040 /* Private define ------------------------------------------------------------*/ 00041 /* Private macro -------------------------------------------------------------*/ 00042 /* Private variables ---------------------------------------------------------*/ 00043 RTC_InitTypeDef RTC_InitStructure; 00044 __IO uint32_t LsiFreq = 0; 00045 __IO uint32_t CaptureNumber = 0, PeriodValue = 0; 00046 00047 /* Private function prototypes -----------------------------------------------*/ 00048 static void RTC_Config(void); 00049 static uint32_t GetLSIFrequency(void); 00050 00051 /* Private functions ---------------------------------------------------------*/ 00052 00053 /** 00054 * @brief Main program. 00055 * @param None 00056 * @retval None 00057 */ 00058 int main(void) 00059 { 00060 /*!< At this stage the microcontroller clock setting is already configured, 00061 this is done through SystemInit() function which is called from startup 00062 file (startup_stm32f0xx.s) before to branch to application main. 00063 To reconfigure the default setting of SystemInit() function, refer to 00064 system_stm32f0xx.c file 00065 */ 00066 00067 /* Initialize LEDs mounted on STM320518-EVAL board --------------------------*/ 00068 STM_EVAL_LEDInit(LED1); 00069 STM_EVAL_LEDInit(LED2); 00070 STM_EVAL_PBInit(BUTTON_TAMPER, BUTTON_MODE_GPIO); 00071 00072 /* RTC Configuration -------------------------------------------------------*/ 00073 RTC_Config(); 00074 00075 /* Wait Until KEY BUTTON is pressed */ 00076 while(STM_EVAL_PBGetState(BUTTON_TAMPER) != RESET) 00077 { 00078 } 00079 00080 /* Get the LSI frequency: TIM14 is used to measure the LSI frequency */ 00081 LsiFreq = GetLSIFrequency(); 00082 00083 /* Turn on LED2 */ 00084 STM_EVAL_LEDOn(LED2); 00085 00086 /* Calendar Configuration */ 00087 RTC_InitStructure.RTC_AsynchPrediv = 99; 00088 RTC_InitStructure.RTC_SynchPrediv = (LsiFreq/100) - 1; 00089 RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24; 00090 RTC_Init(&RTC_InitStructure); 00091 00092 /* Infinite loop */ 00093 while (1) 00094 { 00095 } 00096 } 00097 00098 /** 00099 * @brief Configure the RTC peripheral by selecting the clock source. 00100 * @param None 00101 * @retval None 00102 */ 00103 static void RTC_Config(void) 00104 { 00105 RTC_TimeTypeDef RTC_TimeStructure; 00106 NVIC_InitTypeDef NVIC_InitStructure; 00107 EXTI_InitTypeDef EXTI_InitStructure; 00108 RTC_AlarmTypeDef RTC_AlarmStructure; 00109 /* Enable the PWR clock */ 00110 RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE); 00111 00112 /* Allow access to RTC */ 00113 PWR_BackupAccessCmd(ENABLE); 00114 00115 /* LSI used as RTC source clock */ 00116 /* The RTC Clock may varies due to LSI frequency dispersion. */ 00117 /* Enable the LSI OSC */ 00118 RCC_LSICmd(ENABLE); 00119 00120 /* Wait till LSI is ready */ 00121 while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) 00122 { 00123 } 00124 00125 /* Select the RTC Clock Source */ 00126 RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI); 00127 00128 /* Enable the RTC Clock */ 00129 RCC_RTCCLKCmd(ENABLE); 00130 00131 /* Wait for RTC APB registers synchronisation */ 00132 RTC_WaitForSynchro(); 00133 00134 /* Calendar Configuration */ 00135 RTC_InitStructure.RTC_AsynchPrediv = 99; 00136 RTC_InitStructure.RTC_SynchPrediv = 399; /* (40KHz / 100) - 1 = 399*/ 00137 RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24; 00138 RTC_Init(&RTC_InitStructure); 00139 00140 /* EXTI configuration *******************************************************/ 00141 EXTI_ClearITPendingBit(EXTI_Line17); 00142 EXTI_InitStructure.EXTI_Line = EXTI_Line17; 00143 EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; 00144 EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; 00145 EXTI_InitStructure.EXTI_LineCmd = ENABLE; 00146 EXTI_Init(&EXTI_InitStructure); 00147 00148 /* Enable the RTC Wakeup Interrupt */ 00149 NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQn; 00150 NVIC_InitStructure.NVIC_IRQChannelPriority = 0; 00151 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 00152 NVIC_Init(&NVIC_InitStructure); 00153 00154 /* Set the alarm X+5s */ 00155 RTC_AlarmStructure.RTC_AlarmTime.RTC_H12 = RTC_H12_AM; 00156 RTC_AlarmStructure.RTC_AlarmTime.RTC_Hours = 0x00; 00157 RTC_AlarmStructure.RTC_AlarmTime.RTC_Minutes = 0x00; 00158 RTC_AlarmStructure.RTC_AlarmTime.RTC_Seconds = 0x01; 00159 RTC_AlarmStructure.RTC_AlarmDateWeekDay = 0x31; 00160 RTC_AlarmStructure.RTC_AlarmDateWeekDaySel = RTC_AlarmDateWeekDaySel_Date; 00161 RTC_AlarmStructure.RTC_AlarmMask = RTC_AlarmMask_DateWeekDay; 00162 RTC_SetAlarm(RTC_Format_BCD, RTC_Alarm_A, &RTC_AlarmStructure); 00163 00164 RTC_ITConfig(RTC_IT_ALRA, ENABLE); 00165 00166 /* Enable the alarm */ 00167 RTC_AlarmCmd(RTC_Alarm_A, ENABLE); 00168 00169 /* Set the time to 00h 00mn 00s AM */ 00170 RTC_TimeStructure.RTC_H12 = RTC_H12_AM; 00171 RTC_TimeStructure.RTC_Hours = 0x00; 00172 RTC_TimeStructure.RTC_Minutes = 0x00; 00173 RTC_TimeStructure.RTC_Seconds = 0x00; 00174 00175 RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure); 00176 } 00177 00178 /** 00179 * @brief Configures TIM14 to measure the LSI oscillator frequency. 00180 * @param None 00181 * @retval LSI Frequency 00182 */ 00183 static uint32_t GetLSIFrequency(void) 00184 { 00185 NVIC_InitTypeDef NVIC_InitStructure; 00186 TIM_ICInitTypeDef TIM_ICInitStructure; 00187 RCC_ClocksTypeDef RCC_ClockFreq; 00188 00189 /* TIM14 configuration *******************************************************/ 00190 /* Enable TIM14 clock */ 00191 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14, ENABLE); 00192 00193 /* Reset TIM14 registers */ 00194 TIM_DeInit(TIM14); 00195 00196 /* Configure TIM14 prescaler */ 00197 TIM_PrescalerConfig(TIM14, 0, TIM_PSCReloadMode_Immediate); 00198 00199 /* Connect internally the TIM14_CH1 to the RTC clock output */ 00200 TIM_RemapConfig(TIM14, TIM14_RTC_CLK); 00201 00202 /* TIM14 configuration: Input Capture mode --------------------- 00203 The reference clock(LSE or external) is connected to TIM14 CH1 00204 The Rising edge is used as active edge, 00205 The TIM14 CCR1 is used to compute the frequency value 00206 ------------------------------------------------------------ */ 00207 TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; 00208 TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; 00209 TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; 00210 TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV8; 00211 TIM_ICInitStructure.TIM_ICFilter = 0x0; 00212 TIM_ICInit(TIM14, &TIM_ICInitStructure); 00213 00214 /* Enable the TIM14 global Interrupt */ 00215 NVIC_InitStructure.NVIC_IRQChannel = TIM14_IRQn; 00216 NVIC_InitStructure.NVIC_IRQChannelPriority = 0; 00217 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 00218 NVIC_Init(&NVIC_InitStructure); 00219 00220 /* Enable TIM14 counter */ 00221 TIM_Cmd(TIM14, ENABLE); 00222 00223 /* Reset the flags */ 00224 TIM14->SR = 0; 00225 00226 /* Enable the CC1 Interrupt Request */ 00227 TIM_ITConfig(TIM14, TIM_IT_CC1, ENABLE); 00228 00229 00230 /* Wait until the TIM14 get 2 LSI edges (refer to TIM14_IRQHandler() in 00231 stm32F0xx_it.c file) ******************************************************/ 00232 while(CaptureNumber != 2) 00233 { 00234 } 00235 /* Deinitialize the TIM14 peripheral registers to their default reset values */ 00236 TIM_DeInit(TIM14); 00237 00238 00239 /* Compute the LSI frequency, depending on TIM14 input clock frequency (PCLK1)*/ 00240 /* Get SYSCLK, HCLK and PCLKx frequency */ 00241 RCC_GetClocksFreq(&RCC_ClockFreq); 00242 00243 /* PCLK1 prescaler equal to 1 => TIMCLK = PCLK1 */ 00244 return ((RCC_ClockFreq.PCLK_Frequency / PeriodValue) * 8); 00245 } 00246 00247 #ifdef USE_FULL_ASSERT 00248 00249 /** 00250 * @brief Reports the name of the source file and the source line number 00251 * where the assert_param error has occurred. 00252 * @param file: pointer to the source file name 00253 * @param line: assert_param error line source number 00254 * @retval None 00255 */ 00256 void assert_failed(uint8_t* file, uint32_t line) 00257 { 00258 /* User can add his own implementation to report the file name and line number, 00259 ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */ 00260 00261 /* Infinite loop */ 00262 while (1) 00263 { 00264 } 00265 } 00266 #endif 00267 00268 /** 00269 * @} 00270 */ 00271 00272 /** 00273 * @} 00274 */ 00275 00276 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/