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Arye Perlmutter

Hello:

Anybody can help and give a clue what might be the problem?

When I run my program from FLASH certain routines take about 6 microseconds and when I run the same program from RAM those routines take 18 microseconds. Anybody has a suggestion?

Regards Arye

over 12 years ago

0 Vivek Singh over 12 years ago

TI__Guru** 116401 points

Hi Arye,

If you are seeing this on M3 (Master Sub System) then it is expected. Reason being, RAMs are mapped on System Bus where data/code are accesses goes through same bus where as FLASH is mapped on ICODE/DCODE Bus which means code and data can be accessed in parallel. Also there is cache for flash which helps execution from flash. So for a linear code performance from FLASH execution will be better than RAM.

Regards,

Vivek Singh

0 Arye Perlmutter over 12 years ago in reply to Vivek Singh

Expert 1195 points

Hello Vivek:

I'm talking about routines that run on the c28.

Regards arye

0 Gautam Iyer over 12 years ago in reply to Arye Perlmutter

Guru 192875 points

Hi Arye,

When I run my program from FLASH certain routines take about 6 microseconds and when I run the same program from RAM those routines take 18 microseconds.

That's very strange as it should be the other way around. How're you check the timing? by using Clock profiler in CCS?

Regards,

Gautam

0 Arye Perlmutter over 12 years ago in reply to Gautam Iyer

Expert 1195 points

Hello Gautam:

I'm checking the time wit a GPIO raising it an lowering it and looking on a scope.

Regards Arye

0 Gautam Iyer over 12 years ago in reply to Arye Perlmutter

Guru 192875 points

Arye, instead use Clock profiler for accurate results.

Check this out for more info:

http://processors.wiki.ti.com/index.php/Profile_clock_in_CCS

Regards,

Gautam

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