STM8S/A Standard Peripherals Firmware Library: main.c Source File

00001 /**
00002   ******************************************************************************
00003   * @file    IWDG_Example\main.c
00004   * @author  MCD Application Team
00005   * @version  V2.2.0
00006   * @date     30-September-2014
00007   * @brief   This file contains the main function for IWDG Reset example.
00008   ******************************************************************************
00009   * @attention
00010   *
00011   * <h2><center>&copy; 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 "stm8s.h"
00030 #include "stm8s_eval.h"
00031 
00032 /**
00033   * @addtogroup IWDG_Example
00034   * @{
00035   */
00036 
00037 /* Private typedef -----------------------------------------------------------*/
00038 /* Private define ------------------------------------------------------------*/
00039 /* Private macro -------------------------------------------------------------*/
00040 /* Private variables ---------------------------------------------------------*/
00041 __IO uint32_t LsiFreq = 0;
00042 /* Private function prototypes -----------------------------------------------*/
00043 static void CLK_Config(void);
00044 static void GPIO_Config(void);
00045 static void IWDG_Config(void);
00046 static uint32_t LSIMeasurment(void);
00047 /* Private functions ---------------------------------------------------------*/
00048 
00049 /**
00050   * @brief  Main program.
00051   * @param  None
00052   * @retval None
00053   */
00054 void main(void)
00055 {
00056   /* Clock Configuration */
00057   CLK_Config(); 
00058       
00059   /* GPIO Configuration */
00060   GPIO_Config();
00061 
00062   /* Check if the system has resumed from IWDG reset */
00063   if (RST_GetFlagStatus(RST_FLAG_IWDGF) != RESET)
00064   {
00065     /* IWDGF flag set */
00066     /* Turn on LED1 */
00067     STM_EVAL_LEDOn(LED1);
00068 
00069     /* Clear IWDGF Flag */
00070     RST_ClearFlag(RST_FLAG_IWDGF);
00071   }
00072   else
00073   {
00074     /* IWDGF flag is not set */
00075     /* Turn off LED1 */
00076     STM_EVAL_LEDOff(LED1);
00077   }
00078 
00079   /* Get measured LSI frequency */
00080   LsiFreq = LSIMeasurment();  
00081   
00082   /* IWDG Configuration */
00083   IWDG_Config();
00084   
00085   while (1)
00086   {
00087     /* Reload IWDG counter */
00088     IWDG_ReloadCounter();  
00089   }
00090 }
00091 
00092 /**
00093   * @brief  Configure system clock to run at 16Mhz
00094   * @param  None
00095   * @retval None
00096   */
00097 static void CLK_Config(void)
00098 {
00099   /* Initialization of the clock */
00100   /* Clock divider to HSI/1 */
00101   CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV1);
00102 }
00103 
00104 /**
00105   * @brief  Configures the IWDG to generate a Reset if it is not refreshed at the
00106   *         correct time. 
00107   * @param  None
00108   * @retval None
00109   */
00110 static void IWDG_Config(void)
00111 {
00112   /* Enable IWDG (the LSI oscillator will be enabled by hardware) */
00113   IWDG_Enable();
00114   
00115   /* IWDG timeout equal to 250 ms (the timeout may varies due to LSI frequency
00116      dispersion) */
00117   /* Enable write access to IWDG_PR and IWDG_RLR registers */
00118   IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
00119   
00120   /* IWDG counter clock: LSI/128 */
00121   IWDG_SetPrescaler(IWDG_Prescaler_128);
00122   
00123   /* Set counter reload value to obtain 250ms IWDG TimeOut.
00124     Counter Reload Value = 250ms/IWDG counter clock period
00125                          = 250ms / (LSI/128)
00126                          = 0.25s / (LsiFreq/128)
00127                          = LsiFreq/(128 * 4)
00128                          = LsiFreq/512
00129    */
00130   IWDG_SetReload((uint8_t)(LsiFreq/512));
00131   
00132   /* Reload IWDG counter */
00133   IWDG_ReloadCounter();
00134 }
00135 
00136 /**
00137   * @brief  Initialize LED1 and Key Button mounted on the evaluation board
00138   * @param  None
00139   * @retval None
00140   */
00141 static void GPIO_Config(void) 
00142 {
00143   /* Configure LED1 */
00144   STM_EVAL_LEDInit(LED1);
00145   STM_EVAL_LEDOff(LED1);
00146 
00147   /* Configure Key button */
00148   STM_EVAL_PBInit(BUTTON_KEY, BUTTON_MODE_EXTI);
00149   
00150   /* enable interrupts */
00151   enableInterrupts();
00152 }
00153 
00154 /**
00155   * @brief  Measure the LSI frequency using timer IC1 and update the calibration registers.
00156   * @note   It is recommended to use a timer clock frequency of at least 10MHz in order 
00157   *         to obtain a better in the LSI frequency measurement.
00158   * @param  None
00159   * @retval None
00160   */
00161 static uint32_t LSIMeasurment(void)
00162 {
00163   uint32_t lsi_freq_hz = 0x0;
00164   uint32_t fmaster = 0x0;
00165   uint16_t ICValue1 = 0x0;
00166   uint16_t ICValue2 = 0x0;
00167 
00168   /* Get master frequency */
00169   fmaster = CLK_GetClockFreq();
00170 
00171   /* Enable the LSI measurement: LSI clock connected to timer Input Capture 1 */
00172   AWU->CSR |= AWU_CSR_MSR;
00173 
00174 #if defined (STM8S903) || defined (STM8S103) || defined (STM8S003)
00175   /* Measure the LSI frequency with TIMER Input Capture 1 */
00176   
00177   /* Capture only every 8 events!!! */
00178   /* Enable capture of TI1 */
00179   TIM1_ICInit(TIM1_CHANNEL_1, TIM1_ICPOLARITY_RISING, TIM1_ICSELECTION_DIRECTTI,
00180               TIM1_ICPSC_DIV8, 0);
00181   
00182   /* Enable TIM1 */
00183   TIM1_Cmd(ENABLE);
00184   
00185   /* wait a capture on cc1 */
00186   while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1);
00187   /* Get CCR1 value*/
00188   ICValue1 = TIM1_GetCapture1();
00189   TIM1_ClearFlag(TIM1_FLAG_CC1);
00190   
00191   /* wait a capture on cc1 */
00192   while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1);
00193   /* Get CCR1 value*/
00194   ICValue2 = TIM1_GetCapture1();
00195   TIM1_ClearFlag(TIM1_FLAG_CC1);
00196   
00197   /* Disable IC1 input capture */
00198   TIM1->CCER1 &= (uint8_t)(~TIM1_CCER1_CC1E);
00199   /* Disable timer2 */
00200   TIM1_Cmd(DISABLE);
00201   
00202 #else  
00203   /* Measure the LSI frequency with TIMER Input Capture 1 */
00204   
00205   /* Capture only every 8 events!!! */
00206   /* Enable capture of TI1 */
00207   TIM3_ICInit(TIM3_CHANNEL_1, TIM3_ICPOLARITY_RISING, TIM3_ICSELECTION_DIRECTTI,
00208               TIM3_ICPSC_DIV8, 0);
00209 
00210   /* Enable TIM3 */
00211   TIM3_Cmd(ENABLE);
00212 
00213   /* wait a capture on cc1 */
00214   while ((TIM3->SR1 & TIM3_FLAG_CC1) != TIM3_FLAG_CC1);
00215   /* Get CCR1 value*/
00216   ICValue1 = TIM3_GetCapture1();
00217   TIM3_ClearFlag(TIM3_FLAG_CC1);
00218 
00219   /* wait a capture on cc1 */
00220   while ((TIM3->SR1 & TIM3_FLAG_CC1) != TIM3_FLAG_CC1);
00221     /* Get CCR1 value*/
00222   ICValue2 = TIM3_GetCapture1();
00223   TIM3_ClearFlag(TIM3_FLAG_CC1);
00224 
00225   /* Disable IC1 input capture */
00226   TIM3->CCER1 &= (uint8_t)(~TIM3_CCER1_CC1E);
00227   /* Disable timer3 */
00228   TIM3_Cmd(DISABLE);
00229 #endif
00230 
00231   /* Compute LSI clock frequency */
00232   lsi_freq_hz = (8 * fmaster) / (ICValue2 - ICValue1);
00233   
00234   /* Disable the LSI measurement: LSI clock disconnected from timer Input Capture 1 */
00235   AWU->CSR &= (uint8_t)(~AWU_CSR_MSR);
00236 
00237  return (lsi_freq_hz);
00238 }
00239 
00240 #ifdef USE_FULL_ASSERT
00241 /**
00242   * @brief  Reports the name of the source file and the source line number
00243   *   where the assert_param error has occurred.
00244   * @param file: pointer to the source file name
00245   * @param line: assert_param error line source number
00246   * @retval None
00247   */
00248 void assert_failed(uint8_t* file, uint32_t line)
00249 { 
00250   /* User can add his own implementation to report the file name and line number,
00251      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
00252 
00253   /* Infinite loop */
00254   while (1)
00255   {
00256   }
00257 }
00258 #endif
00259 
00260 /**
00261   * @}
00262   */
00263 
00264 
00265 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/