What is startup data structure for S12ZVM and How it gets intialised ?

ameykhatavkar — Tue, 02 Feb 2016 08:12:36 GMT

Hi,

While going to the start up code I come across the startupData structure.

*********************************************************************************************

STARTUP SECTION

---------------------------------------------------------------------------------------------

Entry point: 0xFE004F (_EntryPoint)

_startupData is allocated at 0xFE00A2 and uses 20 Bytes

extern struct _tagStartup {

unsigned nofZeroOut 1

_Range pZeroOut 0x1200 62

_Copy *toCopyDownBeg 0xFE052A

int nofInitBodies 0

_Cpp *initBodies 0xFE00BD

int nofFiniBodies 0

_Cpp *finiBodies 0xFE00BD

} _startupData;

I understood the code, but I would like to know that, how it gets initialized?

Who is responsible for the same?

And is it always located at address 0xFE00A2 ?

Also Is EntryPoint address (0xFE004F is always same?

Regards,

Amey

Re: What is startup data structure for S12ZVM and How it gets intialised ?

RadekS — Wed, 03 Feb 2016 14:39:32 GMT

Hi Amey,

Please check start12z.c and start12z.h file in your project/Project Settings/Startup_Code.

This structure is used for initialize RAM prior start main() routine. The default bare metal project execute _Startup() function after reset. This _Startup() function will erase and initialize RAM.

Note: If you use ProcessorExpert, the reset vector points to _EntryPoint() instead of _Startup() .

Startup code is placed by linker, therefore location of this code could vary according linker settings and your project size.

Note: prm linker file is in your project/Project Settings/Linker_Files.

You could try for example specifying some part of RAM and filling them by some pattern. For example:

RAM3 = READ_WRITE 0x003000 TO 0x003FFF FILL 0x33;

In that case startup code will initialize this part of RAM prior enter into main() function.

The similar way you could also copy some code from flash into RAM (RELOCATE_TO).

See "c:\Freescale\CW MCU v10.6\MCU\Help\PDF\MCU_Build_Tools_Utilities.pdf" document for more details.

I hope it helps you.

Have a great day,
RadekS

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S12 / MagniV MicrocontrollersのトピックWhat is startup data structure for S12ZVM and How it gets intialised ?

What is startup data structure for S12ZVM and How it gets intialised ?

Re: What is startup data structure for S12ZVM and How it gets intialised ?