Idling with low-speed timer

[cth]

Hi,

I am trying to build a low power device using the nRF51422 SoC without a Soft Device. I need a timer to occasionally wake up the chip and as I read the product specification it should be possible to achieve a current consumption of 250uA when using only the 1MHz low-speed timer and a 16MHz crystal oscillator (PS 3.1, table 22, page 40). However, with an example from SDK 8.0 as starting point and the nRF51 development kit, I have not been able to get the power lower than approximately 550uA. I use the current measurement guideline from the DK user guide. What can be done to lower the current further?

A sub question: When programming using IAR the current consumption is considerable higher until the development kit is restarted. Is it possible to avoid this?

Best Regards, cth

[Susheel Nuguru]

Which SDK example did you use for this timer functionality?

answer to sub question) It is possible that IAR leaves the chip in debug mode after flashing which consumes more power. I do not have IAR setup now, so I cannot confirm this.

[cth]

Thanks for your replies Aryan. I appreciate your help.

I have moved to the gpiote example and removed the use of all libraries. Furthermore I have implemented the sleep function from Carles in this post. However, the current consumption is still the same (~550uA). The value is decreased considerable compared to the original gpiote example without sleep. The device must be in some kind of low power state, just not as low as the 250uA from the PS. I am wondering if there is some parts of the chip such as a regulator I need to turn OFF. I can live with an extra wake up time, just not in the range as when using RTC.