reducing RAM consumption and current

RE: reducing RAM consumption and current

buja — Wed, 17 Mar 2021 14:11:28 GMT

My device will be switching between systemON and systemOFF. I am able to achieve 300nA during systemOFF which is the least as per specification. But during systemON my device is consuming around 900nA. I would like to bring down it to 600nA-700nA by disabling the unused RAM portions. That is my intention.

RE: reducing RAM consumption and current

awneil — Wed, 17 Mar 2021 13:50:56 GMT

[quote userid="102105" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300406#300406"]My system will be in systemON most of the time[/quote]

You mean System OFF most of the time?

Yes, that is the usual approach to minimising energy consumption.

But your actual question was:

[quote userid="102105" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current"]I would like to reduce the power consumption during systemON by disabling unused sections of RAM[/quote]

did you also mean System OFF there ?

RE: reducing RAM consumption and current

buja — Wed, 17 Mar 2021 12:45:57 GMT

Hi Andrew,

Thank you for your reply.

[quote userid="6462" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300397#300397"]You can see that the CPU alone is drawing on the order of a couple of milliamps - so a few hundred nanoamps for the RAM is of no practical consequence at all.[/quote]

My system will be in systemON most of the time. It will wake up only to send a beacon which not very frequent.

RE: reducing RAM consumption and current

awneil — Wed, 17 Mar 2021 12:31:36 GMT

[quote userid="6462" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300390#300390"]is that significant relative to everything else in System ON ?[/quote]

See: https://infocenter.nordicsemi.com/topic/ps_nrf52810/chapters/current_consumption/doc/frontpage.html?cp=4_5_0_4_1

And, for example: https://infocenter.nordicsemi.com/topic/ps_nrf52810/_tmp/gluon/autodita/CURRENT/parameters.id_current_cpu.html?cp=4_5_0_4_1_0_0

You can see that the CPU alone is drawing on the order of a couple of milliamps - so a few hundred nanoamps for the RAM is of no practical consequence at all.

RE: reducing RAM consumption and current

buja — Wed, 17 Mar 2021 12:31:01 GMT

Thank you Andrew for your reply.

[quote userid="6462" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300390#300390"]and is that significant relative to everything else in System ON ?[/quote]

We are extremely concerned about the current consumption. We are trying to get the least possible figures on all scenarios.

RE: reducing RAM consumption and current

awneil — Wed, 17 Mar 2021 12:25:14 GMT

The code is executed direct from Flash - unless you specifically move it to RAM, and run from there.

[quote userid="102105" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300387#300387"]600 to 800nA based on the RAM blocks[/quote]

and is that significant relative to everything else in System ON ?

RE: reducing RAM consumption and current

buja — Wed, 17 Mar 2021 12:22:25 GMT

Thank you for your replies.

[quote userid="6462" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300254#300254"]Note that code is stored in Flash - not RAM.[/quote]

Yes, Would not the code be moved to RAM on startup ? Or the code will be executed from flash only ?

[quote userid="6462" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current/300254#300254"]

Is the RAM's current consumption actually going to be significant in System ON?

[/quote]

As far as I understand, systemON current will vary from 600 to 800nA based on the RAM blocks enabled/disabled. Please correct me if I am wrong.

RE: reducing RAM consumption and current

Amanda Hsieh — Wed, 17 Mar 2021 12:14:46 GMT

Hi,

I agree with Andrew.

Please also check out our Adjustment of RAM and Flash memory guide for details on how to edit RAM and Flash sizes in your application. However, you've added quite a few services to your application, which all will use some RAM in the SoftDevice. You can take a look at this case, where a few ways to reduce the SoftDevices RAM usage has been suggested.

You also could turn off the features in the sdk_config.h if they are not used in the project.

-Amanda H.

RE: reducing RAM consumption and current

awneil — Tue, 16 Mar 2021 23:31:53 GMT

Note that code is stored in Flash - not RAM.

Is the RAM's current consumption actually going to be significant in System ON?

[quote userid="102105" url="~/f/nordic-q-a/72892/reducing-ram-consumption-and-current"] I see that many drivers which I am not using are getting compiled and added to the binary. [/quote]

They might be compiled, but not added to the binary - check linker options.

If they're really not used, then don't compile them.