SDK15.2 FreeRTOS Consumes high current when SD enabled

[Dave_couling]

I've noticed during a project migration that the FreeRTOS on SDK 15.2 seems to consume quite alot of current, 0.8mA when the SoftDevice is enabled.  I've compared to the example HRS FreeRTOS project which also consumes the same high current of 0.8mA  regardless of the Advertising Interval.  This suggests a possible bug in the SDH FreeRTOS module.  I've migrated a project from SDK 12.3 to SDK 15.2. In SDK 12.3 I did not see this order of magnitude of current consumption.  This magnitude of consumption suggests that possible TIMER0 is not disabled between Radio events?    

I've also added the race-condition noted in nrf_sdh_freertos.c 

void SD_EVT_IRQHandler(void)
{
BaseType_t xYieldRequired = pdFALSE;

if(!m_task_created) return;

//xYieldRequired = xTaskResumeFromISR( m_softdevice_task );
vTaskNotifyGiveFromISR(m_softdevice_task, &xYieldRequired);

if( xYieldRequired == pdTRUE )
{
/* Switch the task if required. */
portYIELD_FROM_ISR(xYieldRequired);

}

Any ideas what could cause this, or what has changed from SDK 12.3?

[Susheel Nuguru]

 can you do a simple idle test with the following change in SDK\external\freertos\portable\CMSIS\port_cmsis_systick.c file-> vPortSuppressTicksAndSleep()

#if 0  
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
                uint32_t err_code = sd_app_evt_wait();
                APP_ERROR_CHECK(err_code);
            }
            else
#endif
#endif // (NRFFOSDK-11174)

Notice the addition of #if 0 and #endif which forces the function to use __WFE instead.and see if you have better results?

[Dave_couling]

sd_app_evt_wait(); idles at an even higher current then using _WFE

I've also noted that even placing a while(1){ _WFE();}  shows an idle current of 0.8mA.  Simply initializing the Softdevice is causing this consumption, regarding of whether theres radio activity or not.

[Dave_couling]

If I enforce my own while(1){ sd_app_evt_wait();}  after I initialize the Softdevice,  it Idles at the expected current.  But when I let the port_cmsis_systick.c file handle the idle loop the current consumption goes back up.  In fact with sd_app_evt_wait(); enabled in that file, consumption idles high ~7mA.   I did a compare of my port_cmsis_systick.c compared to SDK 15.2, and they are essentially the same.  Were there any other fixes implemented under the hood for freeRTOS in 15.3?

[Dave_couling]

Please note all my tests have been run on both the PCA10040 and custom hardware. Testing on both my own firmware platform, and the hrs_freertos example in SDK 15.2

[Susheel Nuguru]

7mA does not look normal on tickless idle on PCA10040, can you please give me your project for a quick smoke test.