TMS320F28386S: Flash kernel loaded in flash, running from ram.

John,

I don't believe you can "Copy" the .out file from Flash to RAM, since the .out file would consist of code, data, etc. You can specify individual functions that you want to run from RAM, as you've done in .TI.ramfunc, and then have the corresponding memcpy() in your initialization code.

As an example, you could place a set of functions within a section called isrcodefuncs, and have the following in your linker command file, and then the corresponding CODE_SECTION pragma against every function that you want to be placed in that section.

In this case, the linker defines all the symbols like isrcodefuncsLoadStart, isrcodefuncsLoadSize, etc. which you can use in your code by using the extern keyword.

Linker command file:

isrcodefuncs :      LOAD = FLASH_BANK0_SEC8_9_10,

                                        RUN =  RAMLS5LS6,

                                        LOAD_START(isrcodefuncsLoadStart),

                                        LOAD_SIZE(isrcodefuncsLoadSize),

                                        LOAD_END(isrcodefuncsLoadEnd),

                                        RUN_START(isrcodefuncsRunStart),

                                        RUN_SIZE(isrcodefuncsRunSize),

                                        RUN_END(isrcodefuncsRunEnd),

                                        ALIGN(8)

Extern declaration of linker symbols (e.g. device.h):

extern uint16_t isrcodefuncsLoadStart;
extern uint16_t isrcodefuncsLoadEnd;
extern uint16_t isrcodefuncsLoadSize;
extern uint16_t isrcodefuncsRunStart;
extern uint16_t isrcodefuncsRunEnd;
extern uint16_t isrcodefuncsRunSize;

Memory copy (e.g. device.c)

memcpy(&isrcodefuncsRunStart, &isrcodefuncsLoadStart, (size_t)&isrcodefuncsLoadSize); 

Code:

#pragma CODE_SECTION(ISR1,"isrcodefuncs");

Void function_name(….)

{

}

To further optimize this approach, it is also possible to use the --ramfunc option provided by the compiler to specify that all functions need to run from RAM. This option can also be limited to specific source files. Instead of selecting this for the project, you will right click on the specific source file and select this option. I believe this is equivalent to the .obj options that you've indicated in your Q2 . I don't know the syntax for that off the top of my head. Likewise, if you have a specific library within your executable that you want to run from RAM, you can do that as well, again I don't know the syntax - I'm trying to dig it up.

Refer here for details: https://software-dl.ti.com/C2000/docs/optimization_guide/phase3/memory.html#executing-from-ram

Thanks,

Sira

Wow, Sira! Thank you for the timely and very detailed answer.

You told me what I despaired to hear, adding" #pragma CODE_SECTION "to all of the functions. But you also gave me a lot of good information. I am looking forward to moving forward with this.

The --ramfunc control will be quite useful. It will allow the regular app code to run from flash but my kernels can run from ram while flash is updated.

I don't think I need isrcodefuncsLoadEnd, isrcodefuncsRunStart, and isrcodefuncsRunEnd. Are thy used by the linker? Maybe interesting or useful in a map file?

Again, many, many thanks.

I have noticed many files using this construct where the first argument is the name of the next function.

#ifdef __TI_COMPILER_VERSION__
    #if __TI_COMPILER_VERSION__ >= 15009000
        #pragma CODE_SECTION(exampleError,".TI.ramfunc");
    #else
        #pragma CODE_SECTION(exampleError,"ramfuncs");
    #endif
#endif

Your example above is like this:

#pragma CODE_SECTION(ISR1,"isrcodefuncs");

Void function_name(….)

{

}

What does ISR1 refer to?

Thanks.

John,

You do need the linker variables used in the memcpy() as I pointed out. Yes, you may not need the others in your code.

Thanks,

Sira

Yes, that was a Typo when I copy and pasted from my code. I tried to make it generic and changed ISR1 to function_name.

It should be:

#pragma CODE_SECTION(function_name,"isrcodefuncs");

Void function_name(….)

{

}

Thanks again. Could you tell me why the ".TI.ramfunc" version is used for the higher compiler versions?

John,

If you use the --ramfunc option in your project (or for specific source files), the linker in newer compiler versions (after v15.9) places these in a section called .TI.ramfunc, not ramfuncs. Therefore, it expects the linker command file to define a section called .TI.ramfunc.

This option does not come into the picture if you place specific functions in RAM in your own user-defined sections.

Thanks,

Sira