1) How to segregate secure and non-secure memory regions? 2) How to access secure data using non-secure API's? 3) Can i get any reference manual about that API's?

[Bubbles]

Hi @rb.1​,

I think your question needs a little more context. What is the product you are using? Is that an STM32U5? It the question is about TrustZone, then the documentation about interaction of secure and non-secure is also available from ARM. But generally, the point of secure part is that it cannot be freely accessed by the non-secure part.

BR,

J

[rb.1]

1)Yes, I'm using STM32U585 in that I'm looking into how to segregate secure and non-secure when Trust Zone is enabled.

2)And how to use switch from secure and non-secure applications using which API's any examples?

[Bubbles]

I think it's best if you try looking into the TF-M solution developed by ARM. I's a useful template to develop TZ SW solutions. Our own TZ-enabled SBSFU for U5 is based on that.

Usual approach is to have the secure part as the OS, running NS app for some part of the functionality (UI for example). The app can call OS services which are placed by the linker and the TZ configuration to a section of code memory called "NSC - non-secure callable". The API in non-secure callable are part of the secure enviroment, but with exception that the non-secure can jump to that address.

BR,

J