Guidelines to reduce the size of sram0_shared for Bluetooth apps on nRF5340

[Bogdan Marinescu]

HI, I'm writing firmware on the nRF5340 that uses both the app core and the net core. The firmware uses Bluetooth, so the net core runs hci_rpmsg and "talks" to the app core via IPC using the sram0_shared memory area. The size of this memory area seems to be 64kB for all the nRF5340-based boards in the Zephyr repository. Judging from the git logs, that size seems to have been there since the first commit of the nrf5340dk_nrf5340 target. However, that feels like a lot of memory, and since I can use all the RAM I can get on the app core, I was wondering if I can reduce it, but I don't know how low I can go. I'm using Bluetooth to connect with some simple sensors and for firmware updates, nothing fancy. Does anybody have some experience with this? Besides the obvious "keep on reducing it until something breaks"
Thank you.

[Menon]

Hello,

I am not sure about the configurations and the SDK version you are using here. But have you seen this memory footprint optimization guide inside our SDK documents?

There is also a blog which discusses about optimizing the application in nRF connect SDK. I hope this might provide some assistance

Kind Regards,

Abhijith

[Bogdan Marinescu]

Hi Abhijith,

Thanks for your response. While the links that you provided seem like very good resources, they don't answer the particular question that I posted above, which has to do specifically with the size of the shared SRAM in a multicore configuration on the nRF5340.
I'm using NCS 2.5.1, but I don't know how relevant that is, it appears that the 64kB size for the shared SRAM has been in the source tree forever.

Thanks,

Bogdan