STM8L探索套件學習筆記-獨立看門狗IWDG（十六）

例程展示如何重載IWDG計數(shù)值，IWDG的時間設置為214.7ms。程序采用“Refresh”變量來使能IWDG重載計數(shù)值仿真IWDG復位，并且板上LED4翻轉(zhuǎn)。當按鍵按下，模擬一次軟件錯誤造成程序沒有喂狗，從而發(fā)生復位。如果IWDG復位，系統(tǒng)啟動后LED3會翻轉(zhuǎn)8次，主代碼如下：

void main(void)

{

uint8_t Index;

GPIO_Init(LED3_PORT,LED3_PIN,GPIO_Mode_Out_PP_Low_Fast);

//輸出低電平-高速10M

GPIO_Init(LED4_PORT,LED4_PIN,GPIO_Mode_Out_PP_Low_Fast);

//輸出低電平-高速10M

GPIO_Init(KEY_PORT,KEY_PIN,GPIO_Mode_In_FL_IT);

//輸入浮空-中斷

/* Set PC1 sensitivity to falling edge and low level 下降沿低電平觸發(fā)*/

EXTI_SetPinSensitivity(EXTI_Pin_1, EXTI_Trigger_Falling_Low);

/* Check if the MCU has resumed from IWDG reset */

if (RST_GetFlagStatus(RST_FLAG_IWDGF) != RESET)

{

/* IWDGF flag set */

/* Toggle LED3 */

for (Index = 7; Index != 0; Index--)

{

GPIO_ToggleBits(LED3_PORT,LED3_PIN);

Delay(0x7FFF);

}

/* Clear IWDGF Flag */

RST_ClearFlag(RST_FLAG_IWDGF);

}

/* IWDG configuration: IWDG is clocked by LSI = 38KHz */

/* IWDG timeout equal to 214.7 ms (the timeout may varies due to LSI frequency dispersion) */

/* IWDG timeout = (RELOAD_VALUE + 1) * Prescaler / LSI = (254 + 1) * 32 / 38 000 = 214.7 ms */

/* Enable the IWDG */

IWDG_Enable();

/* Enable write access to IWDG_PR and IWDG_RLR registers */

IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);

/* Set IWDG timeout */

IWDG_SetPrescaler(IWDG_Prescaler_32);

IWDG_SetReload(RELOAD_VALUE);

/* Refresh IWDG */

IWDG_ReloadCounter();

/* enable interrupts by switching to level 0 */

enableInterrupts();

while (1)

{

/* As Refresh is equal to ENABLE no IWDG reset will occur. When Refresh is

equal to DISABLE, the IWDG counter isnt refreshed and IWDG reset will occur. */

if (Refresh != 0)

{

/* Reload IWDG counter */

IWDG_ReloadCounter();

}

/* Toggle LED4 */

GPIO_ToggleBits(LED4_PORT,LED4_PIN);

Delay(0x6FFF);

}

}