watchdog(IWDG)

  1 /*-- private variable --*/
  2 __IO uint32_t space_reloadTM = 250;//define every after 250 ms reload IWDG
  3 
  4 /*-- private function --*/
  5 void NewDelay(__IO uint32_t nTime);//include reload IWDG
  6 
  7 static void IWDG_Config_Enable(void);//config and enable IWDG
  8 
  9 
 10 /*-- main function --*/
 11 int main()
 12 {
 13     IWDG_Config_Enable(); //config and enable IWDG 
 14 
 15     //for test
 16     while (1)
 17     {
 18         Delay1ms(600); //timeout and reset happend
 19         
 20         /*-- never runs here --*/
 21       
 22         //Reload IWDG counter
 23         IWDG_ReloadCounter();
 24     }
 25 }
 26 
 27 
 28 
 29 void NewDelay(__IO uint32_t nTime)
 30 {
 31     uint32_t time_divisor = nTime/space_reloadTM;
 32     uint32_t time_remainder = nTime%space_reloadTM;
 33     uint8_t i;
 34     
 35     /* every after 250ms reload IWDG */
 36     for(i=0;i<time_divisor;i++)
 37     {
 38         Delay1ms(space_reloadTM);
 39         //Reload IWDG counter
 40         IWDG_ReloadCounter();
 41     }
 42     
 43     /* delay the remain time */
 44     Delay1ms(time_remainder);
 45     //Reload IWDG counter
 46     IWDG_ReloadCounter();
 47 }
 48 /*
 49 void Delay1ms(__IO uint32_t nTime)
 50 {
 51   TimingDelay = nTime;
 52 
 53   while (TimingDelay != 0);
 54 }
 55 */
 56 
 57 
 58 
 59 /**
 60  * @brief  Configures the IWDG to generate a Reset if it is not refreshed at the
 61  *         correct time.
 62  * @param  None
 63  * @retval None
 64  */
 65 static void IWDG_Config_Enable(void)
 66 {
 67     /* Check if the system has resumed from IWDG reset */
 68     if (RST_GetFlagStatus(RST_FLAG_IWDGF) != RESET)
 69     {
 70         printf("\n\r");
 71         uart2str(uartbuff,RST->SR,8,2,‘0‘);   //output RST register
 72         printf("Timeout, RST_SR=%s\n\r",uartbuff);
 73         
 74         printf("timeout!!!");
 75         
 76         /* IWDGF flag set */
 77         /* Clear IWDGF Flag */
 78         RST_ClearFlag(RST_FLAG_IWDGF);
 79     }
 80     else
 81     {
 82         //IWDGF flag is not set
 83     }
 84     
 85     
 86     /* --- IWDG Configuration --- */
 87     
 88     /* Enable IWDG (the LSI oscillator will be enabled by hardware) */
 89     IWDG_Enable(); //0xCC
 90     
 91     /* IWDG timeout equal to 250 ms (the timeout may varies due to LSI frequency
 92      dispersion) */
 93     /* Enable write access to IWDG_PR and IWDG_RLR registers */
 94     IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable); //0x55
 95     
 96     /* IWDG counter clock: LSI/128 */
 97     IWDG_SetPrescaler(IWDG_Prescaler_128);
 98     
 99     /* Set counter reload value to obtain 250ms IWDG Timeout.
100      Counter Reload Value = 250ms/IWDG counter clock period
101      = 250ms / (LSI/128)
102      = 0.25s / (LsiFreq/128)
103      = LsiFreq/(128 * 4)
104      = LsiFreq/512
105      */
106     IWDG_SetReload((uint8_t)(0xFF));//510ms
107     
108     /* Reload IWDG counter */
109     IWDG_ReloadCounter(); //0xAA
110 }