nrf52840 zephyr boot failed

[kit j]

i build the zephyr samples/hello_world Demo ,and it can run and print well on BOARD_NRF52840DK_NRF52840.

but this hex file cannot boot up on my own board.

for simplest case, my own custom board only use 4 pins (SWC SWD GND VCC) from this www.aliexpress.com/wholesale

someone suggests set BOARD_ENABLE_DCDC=n but not work for me.

so i need some help

thx!

[kit j]

I can run other firmware(not zephyr baesd) on this board, so i think it has crystal

[Jared]

Hi there,

Can you try to change the LF clock source by adding this to your config file:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

regards

Jared

[kit j]

Sincerely thank you for your reply. 

I managed to run hello_world after setting RC=y XTAL=n.

I'm currently testing Gazell, so I'm still relying on XTAL. because there is no way to transmit 2.4G when XTAL=n. is there any way to test if XTAL is working properly? Because there is XTAL in board‘s schematic. It looks like my board is not working properly with external XTAL. 

[Jared]

Hi,

Can you share the schematic that shows that there is an onboard LFXO?

regards

Jared 

[kit j]

This is ebyte's E73-2G4M08S1C. In the simplest case, I only used SWD SWC GND VCC. In fact, I confirmed that the board booted successfully once and received GAZELL. I guess it was using XTAL then. But somehow it kept going wrong later.

[Jared]

Hi,

kit j said:

because there is no way to transmit 2.4G when XTAL=n

This assumption is not quite correct. The Gazell, BLE and other 2.4 GHz protocol can run with RC oscillator. The only requirement is to have an external high frequency crystal. 

The schematic you shared only have an external high frequency crystal. It doesn't show an external low frequency crystal. 

regards

Jared 

[kit j]

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

 I use this setting and run the demo successfully.  Sincerely appreciate your patience!

[Jared]

Great, can you mark the answer that fixed your issue as "verified" so that others that have the same issue can find the answer easier?

regards

Jared