RE: nRF52840 Custom board wont start under Zephyr

Jeff Seaman — Wed, 15 Dec 2021 15:44:38 GMT

From the Raytac MBT50Q data sheet pg 38

32MHz crystal and RF (VDD) DC/DC inductor (Reg1) are already inside the module.

From Nordic

Case ID: 251512 nRF52840 REG0 & REG1
There is a surprising amount of passives under the RF can of the module - including above capacitor(s).

I think that is answering the Question.

The needed parts are on the Raytac module but not on my board so I have to use the LDO regulator by setting BOARD_ENABLE_DCDC to disabled.

This can be done in the Configure nRF Connect SDK Project tool

or by changing the setting in the board Kconfig file when creating a custom board

config BOARD_ENABLE_DCDC
bool "Enable DCDC mode"
select SOC_DCDC_NRF52X
default y
depends on BOARD_NRF52840DK_NRF52840

Thank you for setting me on the correct path I did not look into the module for the differences in the two boards just the Adafruit schematic

Jeff Seaman — Wed, 15 Dec 2021 12:52:58 GMT

I was just able to get the Board to start I have to disable the DCDC converter.

If you could shed any light as to why that would be a help. For going forward with designs