Reduce nRF7002dk image size

[esisk]

Hello, I'm in the development stage of a product and currently evaluating the nRF5340 as our main processor and nRF7002 as a companion IC for WiFi. Our application can be used in a wide variety of connectivity environments, so we require a WiFi interface, Ethernet interface, a cellular/GPS modem, and BLE. Also, we want to make MQTTS/HTTPS connections to our cloud provider. I've gotten a lot of these individual components to work individually by building our app to run on a nRF7002dk; however, I'm running into issues with the size of the image being too big when I try to include all of the necessary config variables in my build. Is what I'm attempting to do infeasible? My current build is overflowing RAM by 71,272 bytes and Flash is overflowed by 10,160 bytes. I can share my board overlays and configuration files. To be clear, I'm using NCS version 2.8.0, and building an application with nrf/7002dk/nrf5340/cpuapp/ns board as the target.

4336.prj.conf sysbuild.conf 3731.nrf7002dk_nrf5340_cpuapp_ns.conf nrf7002dk_nrf5340_cpuapp_ns.overlay

[Elfving]

Hi Ethan,

What you are asking about is a typical issue. You'll have to figure out what exact Wi-Fi features you require, and configure the rest to consume less. There are a lot of wifi related configs for this as well, this might be interesting, as well as this.

One thing that I feel is obligatory to mention, is that you can also use XiP, though I would recommend not to, due to all the complexities that comes with it. If you are considering XiP, I would rather suggest switching to an nRF54.

Regards,

Elfving

[esisk]

So I'm able to get the app to fit with MCUBoot as long as there's an external flash and no BLE enabled. I'm using the mx25r64 devicetree node as the external flash. My next thought was use the cpunet core to run all of the BLE stack (mentioned here https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/rpc_host/README.html#ble-rpc-host). However, that's making my app even bigger. Is that expected? What's the point of running the network stack on another CPU?

[Elfving]

Hi Ethan,

Nicely spotted, I didn't think that was an option. You'd typically just have the SDC on the network core which would save flash space and CPU, though I see that with this sample you can keep the entire stack there. Though you still need the communication between the Host and the SDC binary that uses RPC libraries and architecture, and now in addition to that you need the communication between the netcore and appcore, which also requires RPC etc. 

So it would make sense if the space you need is a bit more than what just the application takes up. Though I would expect this to still take up less flash than what it would've with some of the BLE stack there as well. Are you saying that moving the entire stack to the netcore made your app bigger than it was with app+host? If so could you try generating a memory report.

I should also mention that this sample is currently supported for development only and does not support all Bluetooth Host APIs.

Regards,

Elfving