stm32f4 __wfi

[Christian Mauderer]

On 20/06/2019 10:57, Jython wrote:
> a GPIO EXTI line,
> rtems idle phrase called __wfi, does it make stm32 enter standby mode?
> so key can not wake up it from sleep function

Please take a look at the reference manual of your chip. Most likely
it's "RM0090 Rev 18" but make sure that's the right part number:

    https://www.st.com/resource/en/reference_manual/dm00031020.pdf

On page 127 there is a description of "Entering low-power mode":

    "Low-power modes are entered by the MCU by executing the WFI (Wait
    For Interrupt), or WFE (Wait for Event) instructions, or when the
    SLEEPONEXIT bit in the Cortex ®-M4 with FPU System Control
    register is set on Return from ISR."

There is also a description for "Exiting low-power mode". For WFI "any
peripheral interrupt acknowledged by the NVIC can wake up the device."
So your interrupt has to be set up.

Your code seems to enable the interrupt. But have you registered a
interrupt service routine? Otherwise you might get problems with an
unhandled interrupt on wakeup.

I only skimmed through the power controller chapter. But it seems that
if you have SLEEPDEEP bit set, you will enter a deeper sleep mode
where peripheral clocks can be disabled. In that state it's possible
that only special pins (like the WKUP) can wake up the processor
again. Please have a detailed look at that chapter to find out all
traps.

Best regards

Christian

> 
> 
>     void keys_init()
>     {
>         // config gpio
>     stm32f4_gpio_set_config(&io_key1);  // PA12
>     stm32f4_gpio_set_config(&io_key2);
>         stm32f4_gpio_set_config(&io_key3);
>     stm32f4_gpio_set_config(&io_key4);
> 
>        
>         //  SYSCFGEN and exit map
>     (*(uint32_t*)0x40023844) |= 1<<14;
>        
>         SYSCFG_EXTICR3 = 0;
>         SYSCFG_EXTICR4 = 0;
>        
> 
> 
>         // EXIT INIT
>     EXTI_IMR |= (1<<12);
>     EXTI_RTSR |= (1<<12);
> 
>         EXTI_IMR |= (1<<11);
>     EXTI_RTSR |= (1<<11);
> 
>         EXTI_IMR |= (1<<10);
>     EXTI_RTSR |= (1<<10);
> 
>         EXTI_IMR |= (1<<9);
>     EXTI_RTSR |= (1<<9);
> 
> 
>         //NVIC_Init
>         //NVIC it group2
> 
>     SCB_AIRCR = 0x05FA0000 | 0x500;
>     // ip Interrupt priority register x
> 
>     //(*(volatile uint8_t*)0xE000E417) = 0xe0;  //23
>         //(*(volatile uint8_t*)0xE000E428) = 0xe0;  // 40
>         (*(volatile uint8_t*)0xE000E417) = 0x50;  //23
>         (*(volatile uint8_t*)0xE000E428) = 0x50;  // 40
> 
> 
> 
>     // 23 40 Interrupt set-enable register x (NVIC_ISERx)
>         // nvic enable interrupter number
>         // 0xE000E100
>         (*(volatile uint32_t*)0xE000E100) |= (1<<23);
>         (*(volatile uint32_t *)0xE000E104) |= (1<< (40%32));
>     } 
> 
> 
> On Thu, Jun 20, 2019 at 4:05 PM Christian Mauderer <list at c-mauderer.de
> <mailto:list at c-mauderer.de>> wrote:
> 
>     On 20/06/2019 05:28, Jython wrote:
>     > hi, it seems that exit key interrupt won't stop sleep mode, why?
>     >
>     > [...]
>     >
> 
>     What do you mean by "exit key interrupt"? I don't know the STM32F4 that
>     well. So please give some more details.
> 
>     I would expect that either only specific interrupt sources can wake up
>     the processor from a deep sleep mode or that you can configure which
>     peripherals are still active. If your "exit key" is a GPIO line with
>     interrupt capability you should have a look at whether the module is
>     still active.
> 
>     Best regards
> 
>     Christian
> 
>     _______________________________________________
>     users mailing list
>     users at rtems.org <mailto:users at rtems.org>
>     http://lists.rtems.org/mailman/listinfo/users
>