Access specific address in SARAM

Marcus Wirebrand

Hi,

I'm looking into writing a boot loader. I want to be able to boot 2 different versions of a firmware. To be able to write the program to memory from flash and execute it, I will require access directly to the SARAM.

Any ideas of how to accomplish this? I would like to be able to grab a file generated with hex55, write it to memory, and execute it.

Will using something like the following, grant me access to the correct address or to some random address in data memory?

int* address = (int *)0x0c;
*address = 0xABCD;

Best regards

Marcus

over 9 years ago

0 Vasantha K over 9 years ago

TI__Genius 12575 points

Hi,

We are looking in to this and you can expect the response on this soon.

Regards

Vasanth

0 Lalindra Jayatilleke over 9 years ago

TI__Mastermind 30365 points

Marcus,

I think this should work. What device are you using? For C5535 SARAM addressing please see table 6-2 of http://www.ti.com/lit/ds/symlink/tms320c5535.pdf for memory block info.

If it's some other C55x device, please refer to the corresponding documentation. e.g table 2-3 for C5515 http://www.ti.com/lit/ds/symlink/tms320c5515.pdf

Just curious, would you have enough space to load both binaries as one executable and use the version as needed?

Regards,
Lali

0 Marcus Wirebrand over 9 years ago in reply to Lalindra Jayatilleke

Prodigy 185 points

I am using the C5535.

Both executables will not fit in memory unfortunately. So I will have to choose the correct one from flash.

I have started implementing the copying of data to RAM and have a followup question. When I want to branch to my new firmware from my bootloader can I just jump to the entry point specified in the firmware image or do I have to do some sort of resetting of the C5535?

When I try to jump to the new _c_int00 something seems to fail.

Currently I'm trying the following:

static void (*appEntry)();

unsigned int entryPoint = 0;

And when data is loaded to memory:

entryPoint = "address from firmware file";

appEntry = (void (*)(void)) entryPoint;

appEntry( );

0 Bill Finger over 9 years ago in reply to Marcus Wirebrand

Genius 3735 points

Have you tried inserting a breakpoint right before you jump to the new entry point, so you can check that the memory has been written correctly?

Also, your 'entryPoint' variable is only 'unsigned int', or 16-bit. Is your entry point within the first 64k of memory?

0 Marcus Wirebrand over 9 years ago in reply to Bill Finger

Prodigy 185 points

Found the problem, it seems I missed the last block of data when I was copying the new firmware to RAM for some reason. After fixing that I get the new firmware up and running.

Thanks
Marcus

Processors

Processors forum

Access specific address in SARAM