nrf_pwr_mgmt_run() with SoftDevice not go to low power

[Bar]

Hello.

I use SDK16 in my project.

Previously when I want to go on sleep I use __WFI(), and get into sleep till interrupt. Because I use The SoftDevice I change the command to nrf_pwr_mgmt_run() as instruct by Nordic . But now it doesn't enter sleep at all. I try also disable the FPU by NRF_PWR_MGMT_CONFIG_FPU_SUPPORT_ENABLED 0 in the sdk_config.h but didn't help.

Why it is so?

Bar.

[Bar]

Hi Jared.

I use my own board where I have a peripheral that take extra power. With __WFI() I get 2ma. With nrf_pwr_mgmt_run()  I get about 8ma.

The relevant code is as follow

#if ((OS_VIEW_IFSELECT != OS_VIEW_IF_JLINK) && (OS_DEBUG == 0))
        if (IdleTicks > 2) // nothing to do wait for interrupt at run time
		{
			// Switch CPU into sleep mode
			nrf_pwr_mgmt_run();
		}

#endif

[Jared]

Hi,

Use a debugger and set a breakpoint inside nrf_pwr_mgmt_run() at line 359 and see if the program hits the breakpoint.

[Bar]

Hi Jored.

It doesn't stop there because I enable the BLE and the softdevice define SOFTDEVICE_PRESENT. So it go to sd_app_evt_wait()

Look at the code.

// Wait for an event.
#ifdef SOFTDEVICE_PRESENT
if (nrf_sdh_is_enabled())
{
ret_code_t ret_code = sd_app_evt_wait();
ASSERT((ret_code == NRF_SUCCESS) || (ret_code == NRF_ERROR_SOFTDEVICE_NOT_ENABLED));
UNUSED_VARIABLE(ret_code);
}
else
#endif // SOFTDEVICE_PRESENT
{
// Wait for an event.
__WFE();
// Clear the internal event register.
__SEV();
__WFE();
}

As I see it when it use BLE with SOFTDEVICE and it is enable it should go there.

Is there a problem about it?

Bar.

[Jared]

Hi,

Sorry for the confusion, you're absolutely correct. Does it go to the WFE() inside the sd_app_evt_wait()? 

[Bar]

Hello Jared.

As  I look into sd_app_evt_wait() I just get to this function 

SVCALL(SD_APP_EVT_WAIT, uint32_t, sd_app_evt_wait(void));

But can't get inside. It is look it send and receive interrupt flags from the SD.

I look on the header explain and I see this:

In order to wake up from disabled interrupts, the SEVONPEND flag has to be set in the Cortex-M
MCU's System Control Register (SCR), CMSIS_SCB.

... The application must ensure that the pended flag is cleared using ::sd_nvic_ClearPendingIRQ
 in order to sleep using this function. This is only necessary for disabled interrupts

I can't find anything about sd_nvic_ClearPendingIRQ

But when look for the SEVONPEND flag I found this discussion: https://devzone.nordicsemi.com/f/nordic-q-a/7107/sevonpend-setting---how-to

WHere he did some work exactly with the some function I try to handle.

Where look for https://devzone.nordicsemi.com/f/nordic-q-a/7107/sevonpend-setting---how-to

So I look for SCB_SCR_SEVONPEND_Msk and the only thing I found was 

SCB->SCR |= SCB_SCR_SEVONPEND_Msk;

which is close by #ifdef PWR_MGMT_SLEEP_IN_CRITICAL_SECTION_REQUIRED

DO I need to open this define?

I also read comment exactly about some issue with sd_app_evt_wait(void) and excessive current. They all take about the FPU and its interrupt panding. https://devzone.nordicsemi.com/f/nordic-q-a/13670/solved-nrf52-sd_app_evt_wait-will-not-go-to-sleep

But I try some like

  // Set bit 7 and bits 4..0 in the mask to one (0x ...00 1001 1111)
  #define FPU_EXCEPTION_MASK 0x0000009F 

      /* Clear exceptions and PendingIRQ from the FPU unit */
      __set_FPSCR(__get_FPSCR()  & ~(FPU_EXCEPTION_MASK));      
      (void) __get_FPSCR();
      NVIC_ClearPendingIRQ(FPU_IRQn);
before 

error_code = sd_app_evt_wait();
but didn't help.
What could be the problem?
Regards
Bar.