NRF52832 won't start

[nick_bike]

Hi,

I've lost hours to this so grateful for your support!

I have a custom board using Raytac MDBT42Q, which has a 32MHz clock in the module and I'm not using an external xtal or DCDC.

When I use the thingy52_nrf52832 as a base board profile, I can program the board and it works fine. However, I can't get this board to compile with mcuboot when CONFIG_BOOTLOADER_MCUBOOT=y

So, I tried the nrf52dk_nrf52832 as a base board profile. This compiles to a working mcuboot image - but when I disconnect the J-Link, the chip doesn't start up. On power cycling, the chip doesn't start up. I've stripped the code to the bare minimum and just set it to turn on an LED, and it doesn't get this far. Seems to be stuck at a hardware startup point.

I've chased down various deadends with UART settings and no luck. Anyone seen something similar?

[JONATHAN LL]

Hi,

Are you able to get the custom board to work with a simple example, like the blinky example with alle configs disabled, what SDK are you using?

Does the device have to be in debug-mode to work or is just having a powered J-Link connector enough to get det device working.

Can you share det schematic, it will be a quick way for me to see if there is anything that seems off.

See if your Software has both DCDC and the external LFXO disabled. If not then that will cause issues.

Regards,
Jonathan

[nick_bike]

Thanks Jonathan. NRF 1.9.1. Your comments got me thinking about the DCDC and I've now fixed this problem by specifically disabling the DCDC. Excellent!

CONFIG_BOARD_ENABLE_DCDC is y by default and but needs one of a number of Nordic boards including NRF52DK_52832. The thing52 is not on the list; so the DCDC gets disabled on the Thingy52 (despite the Thingy52 having DCDC components.)

I checked my boards .config files and found CONFIG_BOARD_ENABLE_DCDC was disabled on the Thingy52 based build , hence why it worked.

Interesting gotcha for anyone making customer boards and not using the DCDC.

[nick_bike]

As an extra answer; it appears that having the J-Link connected in any capacity disables the DCDC, or at least doesn't need it. Hence why it was working when connected.