TMS320F28335: Issue of errata "Memory: Prefetching Beyond Valid Memory"

Jordan Zhou

Part Number: TMS320F28335

Hi,

Customer is using F28335 for their applications. Now we have a doubt about the errata "Memory: Prefetching Beyond Valid Memory".

It's said that:

The C28x CPU prefetches instructions beyond those currently active in its pipeline. If the prefetch occurs past the end of valid memory, then the CPU may receive an invalid opcode.

So, what's the "valid memory"?

Is the case below workable or not? It should OK, my point of view, as the memory after RAML4 is still valid.

RAML4 has only 1 word unused. Application code is saved in RAML4. Global variables are saved in RAML7.

Thanks a lot.

Br, Jordan

over 6 years ago

0 Richard Poley over 6 years ago

TI__Mastermind 27200 points

Hi Jordan,

Correct. "Valid memory" in this case ends at address 0xFFFF. What lies beyond block L7 is invalid. To follow the erratum your code should not come within 8 words of that - so you should not have anything beyond 0XFFF7. Since L5 is vallid memory, you can go right to the end of L4.

Regards,

Richard.

0 Jordan Zhou over 6 years ago in reply to Richard Poley

TI__Genius 10110 points

Thanks a lot, Richard.

Br, Jordan

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TMS320F28335: Issue of errata "Memory: Prefetching Beyond Valid Memory"