MCUBoot nRF52840 NCS v1.5.0 - stuck in bootloader

RE: MCUBoot nRF52840 NCS v1.5.0 - stuck in bootloader

Håkon Alseth — Thu, 22 Apr 2021 09:15:20 GMT

Hi,

[quote user="farhangj"]But more importantly I think the NCS fork of MCUboot needs to be patched with a delay or your suggested line of code to read a random event register.[/quote]

I agree with you 100 %. This is the reason why I reported this internally as bug, and made the mcuboot/bootloader teams aware of this issue.

Kind regards,

Håkon

RE: MCUBoot nRF52840 NCS v1.5.0 - stuck in bootloader

Farhang — Wed, 21 Apr 2021 16:04:22 GMT

Thanks for the reply and explaining the root cause Hakon.

Adding a debounce routine as you mentioned would be great.

But more importantly I think the NCS fork of MCUboot needs to be patched with a delay or your suggested line of code to read a random event register.

Otherwise you'll have units that use MCUBoot as bootloader with the button method lockup (if reset or pwr cycled) and stay in boot waiting for FW update (though there must be a timeout?).

RE: MCUBoot nRF52840 NCS v1.5.0 - stuck in bootloader

Håkon Alseth — Wed, 21 Apr 2021 11:45:03 GMT

Hi,

Since the cpu runs on 64 MHz, and the peripheral interface is on 16M, writes and immediate reads need to be sync'ed towards the slowest clock, which is the peripheral clock here. Reading any random event register will generate a wait condition if required, for instance (void)NRF_TIMER0->EVENTS_COMPARE[0];.

I agree that the non-existing debounce routine here can be highly improved. I'll report this internally as a bug. Thank you for reporting this back to us!

Kind regards,

Håkon