Design Review of nRF52840 Keyboard

RE: Design Review of nRF52840 Keyboard

Turbo J — Mon, 16 Mar 2026 22:34:17 GMT

Redesign.

Debug connector does not have the MCU I/O pin supply voltage (3V3 in your schematic) available. This is a strict requirement for all J-Link debuggers including the ones on the DKs.

I don't see how one would -safely- connect a debugger to your board.

RE: Design Review of nRF52840 Keyboard

hmolesworth — Mon, 16 Mar 2026 18:14:13 GMT

David Did you even try this? "Test by removing R9 and switching back on". Feedback would be helpful ..

RE: Design Review of nRF52840 Keyboard

Ressa — Mon, 16 Mar 2026 17:47:01 GMT

First you need to get SWD access up and running. That's is the only way for connection without any firmware on chip. I cannot find a major issue in design files. Can you share some detail about how you are trying to use SWD ? if possible any log or error to see ? What type of programmer you are using ?

RE: Design Review of nRF52840 Keyboard

David Colburn — Fri, 13 Mar 2026 00:32:36 GMT

Idevzone.nordicsemi.com/.../60W_2D00_Keyboard_2D00_v0.4.zip am not able to connect to the device through USB or SWD. Here are the gerber files.

RE: Design Review of nRF52840 Keyboard

Ressa — Mon, 09 Mar 2026 15:41:30 GMT

Hi,

Can you please share the Gerber files for layout? it is not possible to check the layout with uploaded images. And also a PDF from schematic ?
* Are you able to program the device at all ?
* I don't see any 32 kHz crystal in your schematic. Have you changed the configuration to use internal RC instead of external low freq. crystal ?

RE: Design Review of nRF52840 Keyboard

hmolesworth — Mon, 09 Mar 2026 03:57:04 GMT

One issue lies in pin P0.06 receiving phantom power (aka back-drive) from RGB_POWER due to a schematic error. This will interfere with the nRF52840 reset mechanism as this pin will partially power the nRF52840 internal VDD from +5V/10K via the internal schottky clamp diode before the 3V3 external VDD rail rises.

Test by removing R9 and switching back on :-)

I should add this was only a quick review; if you would post a searchable pdf it would be easier to look further if required.