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

[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.