How to enable DCDCEN in the NCS1.8.0 SDK

[pigno5e]

Dear ,

How do I enable DCDCEN mode if I am using NCS1.8.0 SDK? Is there any Kconfig setting I need to perform to make this available?

Thanks and regards, Kevin

[Øivind]

Hi,

It is enabled by default in the board files for the nRF52840 DK. This is done in zephyr/boards/arm/nrf52840dk_nrf52840/Kconfig. You can try setting CONFIG_BOARD_ENABLE_DCDC=y

If you are using custom board files, it can be enabled with CONFIG_SOC_DCDC_NRF52X.

[pigno5e]

Dear Øivind,

Thanks for your prompt reply.

Yes, I am using a custom board. But instead of creating a custom board files, I use nrf52840dk_nrf52840.overlay to make the configurations the same as my custom board.

Can I do this? Are there any drawbacks of doing this?

In fact, I am currently experiencing some issues with implementing the USB mass storage example using 4GB SD card on my custom board. The host computer can see the drive in the file explorer when plugging in but can't open the drive and keep asking for inserting the SD card. I even soldered the SD card to the desired pins to eliminate any contact issues but still with no luck. Therefore, I am trying figure out if there is any other issues.

Thanks and kind regards, Kevin

[Øivind]

I would suggest that you read through the other board files for nrf52840dk_nrf52840, and make sure that it matches your custom board.

Please make a new ticket specifically for the USB/SD card issue, and I'll help you there. We prefer to keep tickets to a single topic.

[pigno5e]

Dear Øivind,

I will create another ticket if needed.

Just noticed that CONFIG_SOC_DCDC_NRF52X has no prompt and can't be access directly. Is there any other way to config this?

Thanks and regards, Kevin

[Øivind]

First I would check your build files to see if it is already being enabled. You can search for SOC_DCDC_NRF52X and BOARD_ENABLE_DCDC in <build>/zephyr/.config to check. I expect it to be enabled by default.

If it is not enabled, you can try setting CONFIG_BOARD_ENABLE_DCDC=y, which should enable CONFIG_SOC_DCDC_NRF52X.

[pigno5e]

Dear Øivind,

Thanks a lot for your reply.

I've done a bit research and tests and found that -

If I am using below command line to read the DCDCEN status, it returns 0x1 which is correct.

nrfjprog --memrd 0x40000578

However, if I am using below command to access the DCDCEN0 status, it always return 0x0 even after I write 1 to this reg.

nrfjprog --memwr 0x40000580 --val 1

I am not sure why this value seems can't be changed.

Thanks and regards, Kevin

[Øivind]

DCDCEN0 is for high-voltage DCDC. Looks like we started supporting this for nrf52840 in v1.9.0.

[pigno5e]

Dear Øivind,

As it is also a DCDCEN and power regulating related issue, may I also check that if the decoupling cap at DEC5 pin is still required for the nrf52840 ic working properly?

Based on the description in the reference design showing the circuit configuration no. 4 for QIAA aQFN73 on the infocenter webpage, it says the 820pF capacitor is not required for Fxx and later. But I am not sure what does this Fxx stand for or how could I check if my ic is Fxx and later.

As we are encountering some issues with our custom board, will it cause any peripheral function issue if such cap is missing in the design? The silk mark on the IC shows QIAAD0.

Thanks a lot for your kind help.

Thanks and regards, Kevin

[Øivind]

Version D0 needs the decoupling capacitor on DEC5 for an internal 1.3V line. Without the capacitor, there will be increased noise on the TX spectrum, but it should not be responsible for the issues you are seeing.