C2000-CGT: ti-cg-c2000_20.2.5.LTS optimises variable when optimisations are disabled

Sorin Cracana said:

Is there any clean way of telling the compiler not to optimise that away? 

Try the RETAIN Pragma

See section 6.10.24 The RETAIN Pragma in C2000 Compiler User Guide

PERSISTENT works fine but if the variable is not used anywhere in the code, it doesn't

RETAIN doesn't seem  to work at all, even if i try to use the variable 

Is the project using COFF or EABI?

eabi

Created a new project in CCS 11 for a TMS320F280049C using TI compiler v20.2.5 with the following code, where the bootloaderVersion variable isn't used in the code:

typedef struct
{
    int major;
    int minor;
    int patch;
    int build;
    int sha;
} version_t;

#pragma RETAIN (bootloaderVersion)
const version_t bootloaderVersion =
{
    .major = 2,
    .minor = 3,
    .patch = 4,
    .build = 5,
    .sha = 6
};

int main(void)
{
	return 0;
}

Looking at the linker map file shows the bootloaderVersion being placed:

.econst    1    0000a80a    00000005     
                  0000a80a    00000005     main.obj (.econst:_bootloaderVersion)

Without the pragma RETAIN the bootloaderVersion wasn't in the linker map file.

I haven't (yet) attempted to flash the above trivial example, but it does appear to show pragma RETAIN was working as expected.

Sorin Cracana said:

If i don't use this variable anywhere in the code, the values are not stored in flash.

How are you checking for the variable not being stored in flash?

I'm flashing and then looking at the content at the address of that section