nrf5340 custom board programming issue

[sguitton01]

Hi all,

I am developping on a nrf5340 custom board programming through Nrf Connect on VS  Code with a JLink PLUS Compact with SWD

I was able to program the board a few times at the beginning. But after some times I was seeing a consumption increase and the board was not programmable. In ttat state it was still possible to "recover" the board by powering on/off  the board. But now the board seems to switch directly to that problematic state after powering on/off the board so I can't program it at all.

In that state as soon as GND and VTref are connected to the JLink, the jLink led switch the led from yellow to orange meaning "RESET is pulled low (active) on target side." 

Though VTRef is 3V as expected.

Anyway if I try to connect to the board with JLink Commander here's what I have:

ANd on VS COde here's what I see

Do you know why this state is happening? Do you know how I can get out of it? How can I avoid it?

Here's the Hardware setup : 

Thank you,

Sylvain

[Vidar Berg]

Hello Sylvain,

Do you have the optional DCDC inductors and LF crystal mounted on your board? Also, are you able to measure the voltage on the reset pin to confirm if it is pulled low?

Best regards,

Vidar

[sguitton01]

The DCDC inductor is not mounted, but the 32kHz crystal is mounted.
And yes I can measurethe reset pin volatage and it is pulled low.

Thank you,

Sylvain

[Vidar Berg]

Since you don't have the DCDC inductors mounted, please check if the following symbols are disabled in your app core build:

CONFIG_BOARD_ENABLE_DCDC_APP=n
CONFIG_BOARD_ENABLE_DCDC_NET=n
CONFIG_BOARD_ENABLE_DCDC_HV=n

You can see if the symbols are set in the ".config" output.

[sguitton01]

No they are not, I will add it.
Is there a way to recover the boards that are stuck?

Thank you, 

Sylvain

[Vidar Berg]

I'm afraid there isn't an easy way to recover the boards that have been 'bricked'. The only solution I'm aware of is to externally supply voltages to the decoupling pads mentioned by the forum user in this post:  RE: external nRF5340 getting locked up