#pragma DATA_SECTION doesn't work for me (Concerto M3), what am I doing wrong?

Larry Ansell

Intellectual 890 points

HI,

I'm trying to put a const structure with values into flash and not succeeding. I have

#pragma DATA_SECTION(g_appHeader, ".appheader")

const unsigned short g_appHeader[] = {... };

and in my link cmd file I have:

APPHDR (RX) : origin = 0x00203FE0, length = 0x20

and in the SECTIONS I have:

.appheader: > APPHDR

When I look at my map file after compiling with this link cmd file, I see that the APPHDR has zero bytes used! What might I be doing wrong, please?

Thanks for any ideas,

Larry

over 12 years ago

0 Santosh Athuru over 12 years ago

TI__Mastermind 19810 points

Larry,

maybe it is getting optimized out as you haven't yet referred used the array or the function that uses the array is not being called anywhere.

try adding below line to your linker command file.

--retain=.appheader

Best Regards

santosh

0 Larry Ansell over 12 years ago in reply to Santosh Athuru

Intellectual 890 points

Hi Santosh,

Thanks again for your help! You're right that it doesn't get referred to, I was wondering if the "const" would hold it. I want to try your suggestion, it makes sense.

Does the --retain line need to go in a specific location in the linkcmd file? after the Sections? On the same line as .apphdr > ?

Thanks,

Larry

0 Santosh Athuru over 12 years ago in reply to Larry Ansell

TI__Mastermind 19810 points

Larry,

I usually have it at the begining of linker command file, I don't think it matters though. Not sure.

Best Regards

Santosh

0 Larry Ansell over 12 years ago in reply to Santosh Athuru

Intellectual 890 points

Hi Santosh,

Of course, as soon as you had me look there, I saw all the --retains :) Thanks that was an excellent idea. Unfortunately, the map file still has the zero bytes used, (and although I didn't mention it earlier, the .apphdr section doesn't show up in the SECTION ALLOCATION MAP). Do you or coworkers have any more excellent ideas for me to try?

Thanks,

Larry

0 Vamsi Gudivada over 12 years ago in reply to Larry Ansell

TI__Guru* 87145 points

Larry,

Please try declaring the const variable as a static one like: static const unsigned short g_appHeader[ ] = {... };

Thanks and regards,

Vamsi

0 Larry Ansell over 12 years ago in reply to Vamsi Gudivada

Intellectual 890 points

Hi Vamsi,

Thanks for the good suggestion! What turned out to work was Santosh's idea --retain in the linkcommand file, but with g_appHeader instead of .appheader

Thanks very much to you and Santosh!

Larry

0 Santosh Athuru over 12 years ago in reply to Larry Ansell

TI__Mastermind 19810 points

yep...we should specify to retain the variable name not the section name. I always forget that part, thanks for confirming.

Best Regards

santosh

C2000™︎ microcontrollers

C2000 microcontrollers forum

#pragma DATA_SECTION doesn't work for me (Concerto M3), what am I doing wrong?