ZephyrOS project: How to boot/start application from SRAM? (nRF5340 DK)

[ALSCode]

Hello, Community!

Need some help to understand, how to configure project, based on Zephyr, to boot/start it from SRAM?

It may be useful for save FLASH memory resource during development and debugging stage.

Thanks in advance!

[Simon]

Take a look at the sample https://github.com/nrfconnect/sdk-zephyr/tree/v2.6.0-rc1-ncs1/samples/application_development/code_relocation, which demonstrates how to do this.

[Shal]

Hi, 

I'm using Nordic boards to first time and new to Zephyr OS too. I would like to run my application from external flash on nRF5340dk board.

The code_relocation_nocopy sample lets you relocate file by file. Is there a way to load the entire application in the external flash and execute it from there?

Any input would be much appreciated.

[Sigurd Hellesvik]

Hi,

We do not have any sample to move the entire application to external flash.

It is not recommended either, as running the external flash has a higher current consumption and higher latency than running from external flash.

Because of these limitations, I would recommend running most of your application in internal flash, and moving large functions which you only run some times from the external flash.

Regards,
Sigurd Hellesvik

[Shal]

Thanks for the response.

I tried running coremark-pro workloads on the nRF5340dk board. Basically used code_relocation_nocopy to relocate all the coremark related files to external flash XIP and enabled the cache, the performance seems similar to running the same in internal flash. I did not measure the power consumption but at least I do not see any performance issues.

Is there any CoreMark-pro measurement done on nRF5340dk while running code from external flash XIP. Any other documents on performance on external flash XIP would be helpful.   

Thanks.

[Sigurd Hellesvik]

I found a similar question with some answers in  nrf5340: Evaluating Power Consumption of XIP Functions.
Let me know if you have more questions after looking at that.

Regards,
Sigurd Hellesvik