Custom nRF52840 board works in debug mode only.

[xcess]

Hi,

This is my first post and I'm not an expert of Zephyr & nRFs. I have a custom nRF52840 board which I am able to program and debug using nRF52840 DK. I am using Blinky example and is able to see GPIO turning HIGH only under following prj.conf:

CONFIG_GPIO=y
CONFIG_BOARD_ENABLE_DCDC=n
CONFIG_BOARD_ENABLE_DCDC_HV=n
CONFIG_BOOTLOADER_MCUBOOT=y

If I set MCUBOOT=n then I am not able to debug my program. It goes into some infinite loop and never comes into the main. However, when I enable it then I am able to debug my program and able to blink.

But, this only works in debug mode and I have disabled DCDC in prj.conf.

I am unable to execute my program in normal mode.

I have powered the custom board through VDDH from VDD of my nRF52840 DK. I get 3V on VDDH and 1.6V on VDD of my custom board.

I saw somewhere that they were able to solve by using "nrf_power_dcdcen_set(NRF_POWER, false)"? Where can I implement this? Will it help?

Thanks for your help & guidance.

Regards

[Simonr]

Hi

I'll need to get back to you tomorrow with a thorough reply as I didn't get time to look at it today. My preliminary guess is that your custom board has too low voltage in the normal VDD mode, as 1.6V sounds too low, and that would be why you're not able to make it work correctly. What power source are you using to power your board?

Best regards,

Simon

[xcess]

Hi

Thanks for responding.

The VDD of nRF52840 DK is connected with VDD of my custom board and VDDH is not connected. This works with debug mode but not in normal mode though I connected 5V to VDDH. Is this something to do with oscillators? I am using only HF ext oscillator.

Regards

[Simonr]

Hi

Okay, then you must make sure you have configured the internal LF RC oscillator to be used instead of the LF XTAL that is set by default. You can do this by setting CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC is set in your prj.conf file. Note that this is dependent on the clock control config: CONFIG_CLOCK_CONTROL_NRF_SOURCE

Best regards,

Simon

[xcess]

Thanks for replying.

I am able to run blinky on my custom board now but still not able to run Bluetooth/ Beacon sample app. Do I need to upload Softdevice or NCS uploads it? Please guide in running BLE app also.

Thank you very much.

Regards

[Simonr]

Hi

Have you had anyone take a look at your custom board design files and schematics to make sure that it looks okay in terms of antenna tuning? By "still not able to run Bluetooth/ Beacon sample app", I assume you're able to flash it onto the board, but that you don't see any Bluetooth activity on a central device?

From the nRF Connect SDK it should take care of flashing the Bluetooth controller onto the application as well. What app are you trying to run, and have you made a custom board file that fits your design? Please check out the documentation for more info on that.

Best regards,

Simon