Posted on September 19, 2015 at 11:29Hello!
I have a simple program. It has software IRQ to enter Stop mode on return from ISR, and RTC IRQ to wake up and leave Stop mode. RTC IRQ toggles the red LED. On return from Stop mode (return from SW IRQ) the blue LED must be turned off, which never happen. What I see is: the red LED is toggled and the blue LED is always on.
What is wrong ?
Source code:
void EXTI0_1_IRQHandler(void)
{
EXTI->PR = 1;
SCB->SCR = 6; // deepsleep + sleeponexit
}
void RTC_IRQHandler(void)
{
EXTI->PR = EXTI_PR_PR20;
RTC->ISR &= ~RTC_ISR_WUTF;
LED_RED_TGL;
}
int main(void)
{
RCC->IOPENR = 3; // GPIO A,B clock
RCC->APB1ENR |= (1 << 28); // PWR
RCC->APB2ENR |= 1; // SYSCFG
PWR->CR |= (1 << 8); // DBP
RCC->CSR |= (1 << 8); // LSE on
while(!(RCC->CSR & (1 << 9))); // wait for LSE ready
RCC->CSR |= (1 << 16) | (1 << 18); // RTC LSE src clk, RTC ena
RTC->WPR = 0xCA; RTC->WPR = 0x53;
while(!(RTC->ISR & 4)); // WUTWF
RTC->WUTR = 0; // 1 second period
EXTI->RTSR |= EXTI_RTSR_TR20;
EXTI->IMR |= EXTI_IMR_IM20;
NVIC_SetPriority (RTC_IRQn, 2);
NVIC_EnableIRQ(RTC_IRQn);
RTC->CR = RTC_CR_WUTE | RTC_CR_WUTIE | 4; // WUTE + WUTIE + ck_spre
RTC->WPR = 0xFE; RTC->WPR = 0x64;
EXTI->IMR |= EXTI_IMR_IM0;
NVIC_SetPriority (EXTI0_1_IRQn, 0);
NVIC_EnableIRQ(EXTI0_1_IRQn);
LED_RED_ON;
LED_BLUE_ON;
while(1)
{
EXTI->SWIER = EXTI_SWIER_SWIER0; // software IRQ
LED_BLUE_OFF; // turn off blue LED
}
}
