Initialization problem and bricked nrf52833 with nrf connect sdk

[Dan_Y]

Hi,

I'm working on a custom board based on PCA10100, nrf52833 but it seems to be stuck at the function "lfclk_spinwait".

my custom board does not have an external LFCLK.

The crazy thing is, after exiting debug mode my nrf52833 is bricked, I cannot recover, erase or flash anything on device.

I followed this issue:  Initialization problem

and added the CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y" to your prj.conf which solved the problem.

Some additional data:

• SDK:  NCS v2.0.0
• FW: blinky sample.

The full call stack in the image below:

The custom boards are in production ready level, passed QA and work perfectly fine with my application using nrf5 SDK.  In nrf5 SDK if I were to configure my LFCLK incorrect, i would not brick devices to a level were i cannot recover.

Appreciate you look into this.

thanks

Dan

[Dan_Y]

1)

By default these registers are configured to be disconnected..

when we erase or recover with nrfjprog before a program, (that's what west/ncs does) doesn't the UICR get erased too?

2)

and if these register were by mistake enabled, and pin 0.18 is configured to nRESET function.

I still don't understand what does that have to do with not being able to recover and flash?

thanks

Dan

[Kenneth]

Dan_Y said:

and if these register were by mistake enabled, and pin 0.18 is configured to nRESET function.

I still don't understand what does that have to do with not being able to recover and flash?

If pin reset is enabled, and the pin is low, e.g. due to shorted/connected to ground and/or set low by the application, then the chip will enter reset state, when in reset state the chip is not in any valid operation that allow any code to execute or any debugger to be connected through the SWD interface.

Best regards,
Kenneth