Cannot read value using GPMEM over IPC on nrf7002DK

RE: Cannot read value using GPMEM over IPC on nrf7002DK

Simonr — Thu, 17 Oct 2024 12:42:51 GMT

So, me and you both seems to have misunderstood the GPMEM registers here.

As per the product specification:

"General purpose memory
The GPMEM registers can be used freely to store information. These registers are accessed like any other of the IPC peripheral's registers. Note that the contents of the GPMEM registers are not shared between the instances of the peripherals. I.e. writing the GPMEM register of one peripheral does not change the value in another."

As well as the following:

"An IPC event often does not contain any data itself, it is used to signal other MCUs that something has occurred. Data can be shared through shared memory, for example in the form of a software implemented mailbox, or command/event queues. It is up to software to assign a logical functionality to an IPC channel. For instance, one IPC channel can be used to signal that a command is ready to be executed, and any processor in the system can subscribe to that particular IPC channel and decode/execute the command."

So, these IPC events don't contain any data in and of themselves, but just signal to the other core that something occurred. Then data can be shared through shared memory.

Best regards,

Simon

RE: Cannot read value using GPMEM over IPC on nrf7002DK

Riccardo — Thu, 17 Oct 2024 08:14:12 GMT

Hi Simon,

thank you. We can continue here.

Regards

RE: Cannot read value using GPMEM over IPC on nrf7002DK

Simonr — Thu, 17 Oct 2024 08:07:07 GMT

Hi Ricardo

I have created an internal request on how to use the gpmem_get() function here, as I don't see what you're doing wrong either, and will get back to you when I hear from the devs on this. I also saw the new private ticket you created. Would you rather continue there or should we keep updates in this ticket?

Best regards,

Simon

RE: Cannot read value using GPMEM over IPC on nrf7002DK

Riccardo — Tue, 15 Oct 2024 13:10:21 GMT

I appreciate the links you provided but I'm having trouble finding information on how to use nrfx_ipc_gpmem_get(). I don't want to implement an rpm service; I just need to send around 80 bytes of data asynchronously. My plan is to place the data in the GPMEM on one core and read it on the other core.

Can I achieve this using the functions in the nrfx_ipc.h file?

RE: Cannot read value using GPMEM over IPC on nrf7002DK

Simonr — Tue, 15 Oct 2024 10:40:59 GMT

Please check out this case where my colleague Sigurd explains how to let the APP and NET core communicate here: RE: communication in between application core and network core in nrf5340

In general this is a question that's been asked many times, and searching in the DevZone should be helpful as well: https://devzone.nordicsemi.com/search?q=communication%20between%20cores

Best regards,

Simon