Programming flash of nRF5340

[EdwardS]

Hello,

I have to develop application for programming the flash of nRF5340 using SWD interface.

My sequence is below:

1. Erasing and programming

2. Power off or reset

3. Verification

Verification can't be done since reset causes the device to be protected and ERASEALL should be done.

Can I connect the device after power off without executing ERASEALL ?

Thanks

[Vidar Berg]

Hello,

What tool do you use to erase and program the chip? If you use nrfjprog, you should use nrfjprog --recover before the initial programming as described here: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/device_guides/working_with_nrf/nrf53/nrf5340.html#readback-protection

This will set the APPROTECT register on the app and network core to 0x50FA50FA to ensure approtect stays disabled across reboots. 

Best regards,

Vidar

[EdwardS]

Hello,

I develop my own tool to erase and program the chip.

How can I implement "--recover" sequence in my application?

Thanks,

[Vidar Berg]

Hello,

You just need to set the APPROTECT registers to the 'Unprotected' value after doing the full erase.

[EdwardS]

Hello,

As was understood by me the full erase sets automatically the APPROTECT register to the "Unprotected".

Is it correct?

[Vidar Berg]

Hello,

No, it's 0xFFFFFFFF after ERASEALL.