nRF5340 trust zone and cache

[victor zheng]

Hi Team

In nRF5340 Product Specification v1.1 page 117. The CACHEDATA is mapping as secure. But it have trust zone ID 252. So I have below questions

• Does cache only be used by secure code?
• if the answer is no, no matter cache was config as secure or non secure, only the code in same zone can use it. right? 
• if cache only be used by one secure state code, the execute speed will be different in different secure area?

Regards

Victor

[Simon]

Does cache only be used by secure code?

Yes, correct.The CACHE peripheral can only be accessed from secure code, since it's mapped as secure (S).

Read these for more information:

Peripheral access control

Memory map

1.6 Secure vs. nonsecure

if the answer is no, no matter cache was config as secure or non secure, only the code in same zone can use it. right?

 Answer was yes

if cache only be used by one secure state code, the execute speed will be different in different secure area?

 Does this question still apply, since the answer to the first question was yes?

Best regards,

Simon

[victor zheng]

Simon

Because the cache only be used by secure code, the execute speed is different between  secure and non secure code by the influence by cache, right? Thank you.

Regards

Victor