safe task on ble device

[novello]

I was thinking to use mpu to make a "safe task"  that use nrf52840 for the ble NUS comunication and I use  the "safe task" to verify the timeout   and the CRC of the message .

Where i can find some examples that show how to make a protected FLASH and  RAM Ragion  for the "safe task".

Best Regards

Novello G.

[Hung Bui]

Hi Giampiero, 
Could you explain a little bit more on what you want to achieve ? 
Why "verify the timeout   and the CRC of the message" has anything to do with "make a protected FLASH and RAM Region " ? 
Please be noted that a corrupted packet with wrong CRC will be discarded and not be notified to the application.
What do you mean by "timeout" ? 

[novello]

I will add a crc in the nus frame and I have to check if the read message is equal at what i have write  in the previus message . 

[Hung Bui]

Hi Giampiero, 

You can add CRC to the NUS payload if you want.

I just want to remind you that the BLE automatically add CRC check to the payload at Link layer already. So it could be redundant on what you are trying to do here. 

Also note that on nRF52 series we don't have secure and non-secure separation. You can protect an area of Flash from being written. But we don't have an option to make isolated Flash & RAM area for non-secure function. 
For that you may need to switch to nRF53 and nRF54. 

[novello]

Ok and if I use nrf53xx or nrf54xx there is an examples to do that ?

[Hung Bui]

Hi, 
It's possible but you will need to tell what exactly you want to do regarding " make a protected FLASH and  RAM Ragion"