Performance issue between executing code in RAM and flash.

Thomas Song

I am testing 28035 Picolo. I found out something strange regarding execution code in RAM and Flash. I used GPIO toggle example code to test the performance of code execution in RAM and Flash and execution code in RAM is three or four times faster than the execution code in Flash. I reduced from two to one the wait cycle in InitFlash function to get the max performance but this did not make any improvement in performance. Is there any way to expedite the code execution time like enable the prefetch?

Thanks in advance.

Best regards,

Thomas.

over 14 years ago

0 ChrisClearman over 14 years ago

TI__Guru** 119600 points

Thomas

suggest you read

http://processors.wiki.ti.com/index.php/C2000_Flash_Common_Issues/FAQs#Code_Runs_Slower_in_Flash_than_RAM

this is a good appnote

http://www.ti.com/lit/pdf/spra958

Are you sure you are "measuring" correctly?

You need two wait states at 60 MHz on 28035, It depends on how linear your overall code is, but most applications see in total 80-90% effective speed from flash vs. RAM.

If you're toggling an IO after every instruction or something that's not going to give you an accurate representation of what the pre-fetch buffer can do with real code.

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Performance issue between executing code in RAM and flash.