TMS320F28375S: DCSM zone select

Jack Tan80

Part Number: TMS320F28375S

Dear C2000 expert,

From the TRM, it says “ The code security mechanism offers protection for two zones, Zone 1 (Z1) and Zone 2 (Z2). The security mechanism for both the zones is identical. Each zone has its own dedicated secure resource and allocated secure resource. ”

My question is that how to select the zones and make it active? For example, how to select Zone1 or Zone2 and set it active to protecte flash or RAM?

Regards,

Jack

over 1 year ago

0 Hareesh Janakiraman over 1 year ago

TI__Guru* 95315 points

Jack,

You don’t “select” the zones. Rather, you select the block of memory that you want to allocate to each zone. you do this with the GRABRAM and GRABSECT registers. After you do this, you secure the device by programming the passwords and enabling password protection.

Please take a look at the DCSM topic under Security and Safety Peripherals in the C2000 Academy: https://dev.ti.com/tirex/explore/node?node=A__AXPub7FCoHiLY8nrlHuDFQ__c2000Academy__jEBbtmC__LATEST

0 Jack Tan80 over 1 year ago in reply to Hareesh Janakiraman

Mastermind 7100 points

Hi Hareesh,

Thanks for your spporting here.

There are 2 identical GRABRAM and GRABSECT registers inside each zone1 and zone2. What I'm understanding is that configuring Z1-GRABRAM and Z1-GRABSECT are using ZONE1 for security zone, configuring Z2-GRABRAM and Z2-GRABSECT are using ZONE2 for security zone. Is it correct?

If my undersing at above is correct, and if both zones are configured with different value, which zone will be used in this case?

Regards,

Jack

0 Hareesh Janakiraman over 1 year ago in reply to Jack Tan80

TI__Guru* 95315 points

Jack Tan80 said:
What I'm understanding is that configuring Z1-GRABRAM and Z1-GRABSECT are using ZONE1 for security zone, configuring Z2-GRABRAM and Z2-GRABSECT are using ZONE2 for security zone. Is it correct?

Yes.

Jack Tan80 said:
if both zones are configured with different value, which zone will be used in this case?

Sorry I don't understand. What do you mean by "different value"? Different value for what?

Jack Tan80 said:
which zone will be used in this case?

Again, I don't understand. Used for what?

Please review the Academy material and the TRM chapter and let me know your specific question.

0 Jack Tan80 over 1 year ago in reply to Hareesh Janakiraman

Mastermind 7100 points

Hi Hareesh,

Please see below screenshot from TRM, there are 2 OTP locations that can be used to configure ZONE1 and ZONE2.

What my question is that if both OTP Flash are configured, how does the MCU knows which zone is used?

Thanks,

Jack

+1 Hareesh Janakiraman over 1 year ago in reply to Jack Tan80

TI__Guru* 95315 points

Secure resources are individual flash sectors and RAM blocks. Using GRABSECT and GRABRAM registers, these resources can be assigned to either zone1 or zone2. So, both zones are used. Access to these resources will be governed by the security settings of the zones they are assigned to.

0 Jack Tan80 over 1 year ago in reply to Hareesh Janakiraman

Mastermind 7100 points

Hi Hareesh,

I think I have found the info from TRM, that would help me understand how does RAM and FLASH assigned to which zone?

Regards,

Jack

0 Hareesh Janakiraman over 1 year ago in reply to Jack Tan80

TI__Guru* 95315 points

Correct.

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TMS320F28375S: DCSM zone select