How to reduce the free rtos power consumption in idle mode?

[Hsu]

Hi Sir,

As reference below link, and we can find the Tickless IDLE enabled ~700uA in SDK 15.2

https://devzone.nordicsemi.com/f/nordic-q-a/24733/nrf52840-sdk-14-0-0-and-tickless-idle-freertos---some-suggestions

1. Does the ~700 uA is the lowest idle current?

2. from devzone, some discussion can reduce the idle current below 100 uA, any suggestion we can reach this target?

Thank you.

Han

[Susheel Nuguru]

1. Does the ~700 uA is the lowest idle current?

 With the advertising/connection parameters, it is the lowest you can see. But ofcourse you can reduce it more by increasing the adv/conn interval.

 

2. from devzone, some discussion can reduce the idle current below 100 uA, any suggestion we can reach this target?

 Like I said above, the consumption int he examples we gave depends very much on the adv/connection interval. These values are very close to the one examples which behave the same but without the RTOS. So the RTOS overhead power consumption is not big.

[Hsu]

Hi Susheel,

If I want to test w/ "SDK_15.0.0\examples\ble_peripheral\ble_app_hrs_freertos", how do I modify the code to make the system run in idle mode and see the 700uA idle power consumption?

is it correct to comment the function "vTaskStartScheduler()"? when commented, I saw ~70 uA, but I'm not sure it works in idle mode.

Thank you.

BRs, Han

[Susheel Nuguru]

commenting out vTaskStartScheduler will make the system do nothing as the RTOS kernel will not start until you call this function. You should uncomment it and do a fix mentioned in this thread in my reply marked in green. 

In that example, the tickless idle mode is already enable so you do not need to do anything else apart from applying the patch i mentioned in the link and uncommenting vTaskStartScheduler