Changing MSP430 startup adress

Usually, the linker picks a suitable start address based on the segment definitions in its command file (which is specific to the MSP used).

In C, you jsut write a main funciton and the linker will put it somewhere and do all the necessary stuff. Including addign some startup code that initializes variables, then pointeing th ereset bvector to this startup code and jumping from this code to the beginning of your main

However, you can manually set teh reset vector to point to any symbol or address you want and the MSP will jump there after reset.
To place your code there, you can change the linker command file and define a segment that suits your needs and put your code into this segment, or you can specify a fixed address for the code (in assembly, the ORG directive). In C, thsi is compiler specific, as the C standard does not include this kind of manipulation.

However, usually, there is no need at all to care for the location, unless you're doing something very specific.
For further, more specific info, you should provide information why you want to mess with the memory mapping of your code.

paddu said:

is it possible to change the Start adress to a known address

If you look at your project's memory map (/debug/[project].map), in the .text section you'll see an entry like:

00002a0a    00000016     main.obj (.text:main)

The first number is the main function's address.

If you want to start your project at a certain memory location, you can edit the project's linker file.  There will be a section like this:

MEMORY
{

...
FLASH                   : origin = 0x1100, length = 0xE900

By default the origin is at the start of the device's program memory, so there's usually no need to change it.  However, it's as easy as changing the origin to your new starting address and updating the length appropriately.

Hi,

Thank you all for the reply,

Actually we want to change the startup address(_c_int00) to a different location.

like the one mentioned here in the below link.

http://e2e.ti.com/support/microcontrollers/msp43016-bit_ultra-low_power_mcus/f/166/t/67507.aspx

But I am confused and I couldn't find any standard procedure mentioned in the CCS user guide or Compiler User guides.

From an old website I found the procedure in case of IAR as below.

1. Copy cstartup.s43 to your own project directory.
2. Edit it to suit your needs (__low_level_init is in it)
3. Assemble it
4. Add "-A cstartup" to your project's XCL file.
5. Link it

paddu said:

we want to change the startup address(_c_int00) to a different location

I am just guessing, paddu might want a different c-startup routine, instead of a different location for c-startup routine.

Thank you for the comments,

Actually our customer's application has a requirement for two sorts of program in the flash.

Other than the main program(the actual application) , they need a start up program which checks the checksum of the 

main program and transfers the control to main program if there is no problem with the checksum.

I thought, in order to make the verification routine to be apart of the rest of the code to be verified.

I am sorry for the above confusion,

after studying other posts I think that there is no need to change the startup routine

and using linker command file we can place the main program and the verification routine

into different flash locations.

Please let me if there a better way of implementation.

PS: Just for the curiosity I would like to know what is the easiest way change the startup address(_c_int00) 

    to a different location.

Regards.

paddu.

paddu said:

Actually our customer's application has a requirement for two sorts of program in the flash.

Putting two C programs into one MSP isn't a good idea since both programs usually have their own vector table usage etc. Of course one could switch between the two tables by reprogramming the vector table, but this is dangerous since during reprogramming the table, any power fail will leave the device unresposible.
There are MSPs which can move the vector table to the end of ram, so a 'supervisor' can switch programs. This requires, however, soem effort.

Usually it is much, much easier to join the two programs into one.

paddu said:

Other than the main program(the actual application) , they need a start up program which checks the checksum of the main program and transfers the control to main program if there is no problem with the checksum.

And all problems are gone with a snap.

Hi Jens,

Thank you for the information.

Actually the application itself would be updated through USB (DFU).

There are a possiblities that the application program is not updated 

properly or any other issue that would that the application program is corrupted,

so after the application is updated we need to check the integrity of that program.

So if we have a separate start up program in a flash area 

which is not updated through DFU, we can check the integrity of the updated

main application.

Regarding the vector table, I think we can make a copy of the original vector table

and place it in the appplication area.

After power up, the start up code checks if application program has any problem

and makes a indirect jump to the copied vector table and runs the main program from there.

But I haven't tried to implement it yet,

please let me know if there is any application or any reference to implement this kind of application.

Regards.

Paddu.

One thing you may want to try is using the linker command file to partition off a section of the flash memory for each application, and possibly the vector tables.  Be aware of the starting address for each flash segment when you do this, or you may accidentally erase unintended data when you re-flash the memory (see the "flash memory controller" chapter of the MSP430 user guide).