How to load app and network core of nrf5340 at once

[Divya BM]

Hi,

I am trying to bring up open AMP application on nrf5340.

As previously known, this is used for exchanging specific data between the app core and the network core.

The sample application consists of 2 main.c, one for each core. How can this be run on nrf5340?

1. Can we build the corresponding application as nrf5340pdk_nrf5340_cpunet and nrf5340pdk_nrf5340_cpuapp and flash the 2 individual solution zephyr image? Will this work?

2. If not, how to load both the cores at once? We are using SEGGER embedded tool for flashing and debugging.

3. We went through the hci_rpmsg sample application in the nrf5340 PDK. Here, there is a single main file and the flow is similar to openAMP. However, is this data transfer across app core and network core? If so, how can we understand what gets loaded to the app core and what will be loaded to application core?

Regards,

Divya

[MariaG]

Hi,

1. Building the separate parts and flashing the two resulting images has worked for me.

2. In my experience, SEGGER does not seem to support flashing to both cores at once. My best advice at this point is to flash the images with nRF Connect Programmer.

3. When building hci_rpmsg for the network core, a bluetooth host stack should be programmed to the app core. A friend of mine put together this simple example based on hci_rpmsg and the rpmsg_nrf53 driver found in zephyr\drivers\bluetooth\hci. Maybe that example can help illustrate the functionality. Please mark that it has omitted bluetooth functionality. 
I general, applications for the app core which needs hci_rpmsg support can include it as a sub-image, which you can find more info on here. The result from a multi image build will be both individual images for the two cores, as well as a merged image. 

Regards,

Maria

[Divya BM]

Hi Maria,

Thanks for the support.

The example you provided was helpful. With this example and nRF Connect Programmer, the data exchange is possible. However,

1. We cannot see the network core's output on the console by default. Refer here. Is there any way, this can be enabled?

2. Also, once we use nRF Connect Programmer to flash, is there any possible way to debug the loaded program like how we do in SEGGER?

Regards,

Divya

[MariaG]

That is good to hear! 

1. The pins described in the documentation you provided can be connected on the PDK with jumper wires. 

2. I don't personally have any experience on debugging with SEGGER, but i found this case which might help you. 

Best of luck,

Maria

[Divya BM]

Hi Maria,

Will try out the two things you suggested. 

If we were to create multi-image build for the use-case like open AMP/ the one you suggested, is there any sample available in zephyr of nrf5340 for reference? This will help in debugging easily.

Regards,

Divya