Readback protection.

[Regio]

How can I protect nRF52840 from flash (excluding virtual pages) readback.

I want to have a virtual site available for reading via nRF Connect.

[Kenneth]

I do not see any easy way to achieve this, it's not possible to only partially enable readback protection over SWD. So you would need to protect the entire flash, and for instance the application can have some commands over a serial interface (for instance UART) where the application make it possible to access only part of flash.

Best regards,
Kenneth

[Regio]

Hi  Kenneth,

thank you for your  answer.

I'm testing the application on an nRF52840 Dongle, you could be more specific for this case.

Well thank you.

Best regards,

Regio

[Kenneth]

The USB MSC seems like a good starting point:
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/usbd_msc_example.html

If you enable readback protection in UICR (see APPROTECT register), you can still run the above example and allow data to be write/read through USB mass storage class.

[Regio]

Hi Kenneth,

thank you for your  answer.

The USB Mass Storage Class module will support SPI/QSPI flash/SD cards and RAM/Empty devices, but does not provide a block device class for internal flash.

I removed a part of the QSPI and used RAM and FLASH only to simulate the MSC. But every time I insert the dongle into the computer, it wants to format it.

Can you suggest a way to solve this problem?

In short, at the moment it works like this:
I upload flash (virtual pages nRF52840 Dongle) via nRF Connect - Programmer as a part of .hex file via "Save as file" (there are a few thousand records). This is not possible when using "Approtect".

Well thank you.

Best regards,

Regio

[Kenneth]

Check out this thread:
https://devzone.nordicsemi.com/f/nordic-q-a/70570/nrf52840-sdk16---usb-msc-example---how-to-check-if-fat-volume-exists