SC58x: How to share external DDR memories between core0, core1 and core2?

Hi Jhon,

LDF files are specific to SHARC Core. Core 0 is initialized to external memory. ARM core does have a knowledge of DDR memories and has GNU ARM tool chain to link .ld files.

If you are referring to the .ldf specific changes, you can look into the Linking Multiprocessor Systems and the related details in CCES Linker Manual. Here's the link for the same - http://www.analog.com/media/en/dsp-documentation/software-manuals/cces-LinkerUtilities-manual.pdf 

Hope this helps. Let me know if you have any further queries related to this.

Regards,

Nithya

Dear Nithya:

I'm back to the question. I'm using SC584, CCES2.6.0.

In core SHARC0, I declared a big matrix (named "buff" for example) in external ddr2 memory, after the program in SHARC0 has filled the matrix, I want to read it in SHARC1 and do some processing. But I don't know how to find the address of "buff". Maybe I can check the linker map file of core SHARC0 to find the address of "buff", and then use hard coded pointer in SHARC1 to access "buff". But this is not reliable. Because every time the project is re-compiled, the address is about to change.

Is there a good way to reference a variable in another core? Especially in external ddr memory.

Thanks.

Best Regards,

Jhon

Dear Nithya:

I also read the ldf document, it seems that using SHARED_MEMORY{} command can solve my problem, but there is no example projects.

Since the SC584 has 3 cores, and each project has a individual folder with all files in it, I'm not sure how to use the SHARED_MEMORY command. Below is my guess:

Both the two sharc cores (core1 and core2) has a app.ldf file, so I need to modify both of them, adjust the 2 default ddr2 memory section for each sharc core, and add a shared DDR2 memory section.

I need a "shared_memory.sm" file, so I write a data.c in project core1, which only include a big matrix "buff", after compiled, a "data.doj" is created. Then I use the code in page 5-28 to modify app.ldf for project core1.

Then the problem comes for project core2. How to write the SHARED_MEMORY, INPUT_SECTION and LINK_AGAINST command in "app.ldf" for core2? Should I use the "shared_memory.sm" "data.doj" created by project core1?

Thanks.

Best Reards,

Jhon

Were you able to get going? Apologies for the delay in getting back.

You can look into the Linker Description manual which gives a detailed explanation of the steps to be done in Pg 5-27. Here's the link for the same- https://www.analog.com/media/en/dsp-documentation/software-manuals/cces-LinkerUtilities-manual.pdf  

If you're still facing issues and need to understand the LDF changes to create shared memory section for your project, you can send a mail to processor.tools.support@analog.com.

Hello,

If it is a new query can you please create a new discussion?

Best Regards,

Jithul

Hi, have you solve the problem . I need to use share memory. according the pdf, the buidl is failure. 

Could ADI provide a demo for to use share memory.?