Programming custom board with nRF52840

[Adrian1504]

Hello,

I have developed a custom board for the nrf52840 with the QFAA QFN48 package.

I am trying to program it with my nRF52840, I am using P20 of the DKconnecting the following way:

2 & 3	VDD of my device which is powered by 3 V
4	SWDIO
5	SWDCLK
7	Reset
8	Ground

When I connect it my VSCode does not detect any device. I also tried to detect it with the nRF Connect Desktop, but still no success. Am I connecting something wrong?

I will leave the image of my schematic and pcb.

Thank you so much for your time.

Adrian Lopez.

[ketiljo]

The connection to the DK seems to be correct. The schematic looks ok as well so you might have solder issues. 

The layout isn't good though, so even if you get this working, the performance will be bad. Take a look at the reference layout. Most components are placed where they are of a reason: https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/reference-layouts/nrf52840/nrf52840-qfaa-reference-layout-1_0.zip

The RF section is critical:

And the placement of the decopling caps; they need to be close to the pins in the schematic. 

The antenna need tuning components, see this whitepaper, chapter 4.2: https://docs.nordicsemi.com/bundle/nwp_017/resource/nwp_017.pdf