[Solved] MDK makerdiary 52840 dongle unable to pair with nicenanov2 split but is recognized

[tall summit]

Status: MDK 52840 dongle after flashing works by itself. Recognized by OS and ZMK studio but cannot be paired with halves which are both nnv2.
Tested: The same build works with Xiao Sense BLE and the Supermini NNv2 clone and the NNv2 without changing any settings.

Perhaps some other flash/memory offset is needed? Which is odd because the dongle itself works flawlessly but does not pair. The only repos I have found to try to fix something are:
https://github.com/jibingeo/zmk-config-onekey/
https://github.com/tungd/corne-mdk

I am reticent when it comes to posting my own repo as I just started coding after a long 15 year gap and also am new to using git and discord, so I feel I don't want to make any errors with posting rules or the code which I jumbled up as a patchwork. Of course it might not be hard to find it with a cursory search.
Thank you for your time and have a wonderful day.

MDK makerdiary 52840 dongle unable to pair with nicenanov2 split but is recognized and works in OS

[sudden snow]

I don't think anyone will mind what state it's in, it will be helpful to post your config

[tall summit]

I recently read the history of zmk here: https://kbd.news/ZMK-A-History-2222.html and it was beautiful and inspirational. Please convey my regards to Pete and once again, thank you for all the work and care, particularly the endless hours you answer questions and troubleshoot over here on discord.

[sudden snow]

IANAL but I wouldn't worry too much about it personally. I don't think anyone will mind it, but if something is especially tricky it might be good to give credit in a comment or so somewhere.

This depends on the license of the original hardware models and code etc., not an easy question to answer. But follow the license file if the original has one

AFAIK, technically, if a repo doesn't have a license you have no right to copy/modify, but most people seem to ignore that anyway

I'd say it is a friendly community in general so unless you are taking people's work and selling it for profit (which unfortunately happens a lot these days, with AliExpress sellers), I wouldn't worry too much

As for your actual problem, I am guessing (couldn't check your whole config) you don't have flash enabled for the dongle. Normally some additional settings are set to use boards that are in Zephyr, but not augmented by ZMK. They look like this, which includes flash for settings storage: https://github.com/zmkfirmware/zmk/blob/main/app/boards/seeeduino_xiao_ble.conf

[tall summit]

I added that and tried it but it still didn't work.

[sudden snow]

(What that file does is augment the existing board in Zephyr seeeduino_xiao_ble, so you can use it as a board and have things work as expected)

[tall summit]

Roger about the instructions for sharing the files and the general outlook on how to manage the copyrights.

[sudden snow]

What I'd usually do to debug is check the build outputs for certain things: https://zmk.dev/docs/troubleshooting/building-issues#diagnosing-unexpected-build-results

• CONFIG_ZMK_{USB,BLE} are set
• CONFIG_ZMK_SPLIT and CONFIG_ZMK_SPLIT_ROLE_CENTRAL are set
• CONFIG_ZMK_SPLIT_BLE_CENTRAL_PERIPHERALS is set (to 2, in your case)
• Probably double check the flash settings linked above are set as well, so pairing keys can be stored

[tall summit]

I see. I am trying to keep up. Thank you for the hints and direction.

[sudden snow]

Also forgot to say, this is very nice to hear 🙂

[tall summit]

I am a bit confused. Those flash settings are for the xiao but I'm going to try using the MDK as the dongle and 2 nnV2s as the peripherals. WOuld those flash settings still apply?

[sudden snow]

If config all looks good, then I'd try going through the settings reset procedure to make sure previous pairings are all cleared: https://zmk.dev/docs/troubleshooting/connection-issues#split-keyboard-halves-unable-to-pair. These docs apply to three part (with dongle) keyboards as well

[sudden snow]

I mean you'd set those same settings for your board somewhere (config/nrf52840_mdk_usb_dongle.conf should work, IIRC, yes

I am making some assumptions here, such as your dongle board being similar enough to Xiao BLE to have the same capabilities

And that its flash partitions are already set appropriately in the Zephyr board

[tall summit]

Got it. I double checked if the settings are cleared but that didn't help. Yes, those were the ones I used but it didn't take. Anyway, I already made a variety of dongles and splits works together with a variety of screens. This was the only one I was having a problem with. So it's not a critical problem.

Don't waste too much of your time on it. I appreciate the general direction. I'll double check and report back if I amake any progress.

[sudden snow]

This, I can't find in Zephyr dts actually. But you should be able to see it in the file here https://zmk.dev/docs/troubleshooting/building-issues#devicetree-related-issues if they are set

OK, sounds like you know what you are doing in general. There is likely some problem with this board related to some things missing, due to not being officially "supported" in ZMK

In general, for using with ZMK needs USB, BLE, and settings storage to flash working, but I am kind of repeating myself here

(not a dig on you, but my inability to communicate better)

[tall summit]

One last query if I may- the flash settings in the old repo which I linked originally for corne with the MDk (not mine) used a flash offset to flash the dongle. I assume that part is for a different older nordic bootloader which does not affect the newer adafruit nf2 bootloader I'm currently using.

[sudden snow]

Oh, I haven't checked that, actually

[tall summit]

So these flash settings you mention have to be in the .conf file which is separate from those other flash settings for the bootloader because I can flash the dongle with both the settings reset file and the uf2 firmware without issue and the OS recognizes it.

For example - https://github.com/tungd/corne-mdk/blob/main/config/boards/arm/nrf52840_mdk_usb_dongle/fstab-stock.dts

[sudden snow]

I see the flash now, OK

[tall summit]

This is what I tried using earlier

[sudden snow]

Right, that file exists in Zephyr already, so you are using the same partitions. There are two scenarios I've seen happen when partitions are wrong:

• fail to flash (doesn't reboot after copying to bootloader), e.g. this happens if you try to flash partitions with SD (softdevice) on top of partitions without SD
• flashes and overwrites some existing partitions (like SD), which means you can't flash with a previous partition setting but can keep flashing with the same. This happens e.g. if you flash non-SD partitions on SD

Maybe you are in the second scenario, but it means you can still flash OK with your current settings. So it is likely not currently an issue.

Then, the .conf settings are separate. Those enable you to use the settings subsystem to store e.g. pairing keys to flash, so they need to be enabled if you want pairings to persist across boots

[tall summit]

Do I need to include a different clock for the dongle or am I asking something stupid? I tried including CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_30PPM=y but it didn't make any difference.

[sudden snow]

These look correct for the .conf, yes

[tall summit]

Got it.

[sudden snow]

I would assume that the clock stuff is set correctly in the board settings, so I wouldn't think they'd need touching?

[tall summit]

I think you have narrowed it down to the possibilities- the second scenario seems likely

I will try either accessing the dongle using segger or using nordic tools

Double check on the softdevice issue and lets see if I make any progress.

[sudden snow]

I think we are exceeding my experience here, so hopefully my pointers will be useful for you to continue

[tall summit]

All of this is really overwhelming. I started with my first board in the first week of January this year from zero. Thank you for your support. I just found out about the ZMK discord through the website recently. Feels uncomfortable asking for help when I made it this far just looking at other peoples comments on reddit and repos on git.

Have a wonderful day and keep up the amazing work. It might seem to you sometimes like I am flattering beyond reason but I mean it. I have been down for a while and this whole experience with keyboards has brought me a lot of smiles and joy.

No need to reply further.

[sudden snow]

No worries, never feel uncomfortable asking help. You did your homework before asking, which is all that matters

And welcome to the hobby 🙂

One last thing, if you haven't come across it, https://zmk.dev/docs/development/usb-logging might be useful. But you might need to set it up for your board first: https://zmk.dev/docs/development/usb-logging#adding-usb-logging-to-a-board

[tall summit]

Was just reading that exact thing to debug. On the same wavelength here.

[tall summit]

HOLY SHIT!

It works! You genius! This is beyond my wildest dreams. I just can't believe it.

I added the config code for the https://github.com/zmkfirmware/zmk/blob/main/app/boards/nrf52840dk_nrf52840.conf

The previous config was either directly taken from that old repo or a mix of my other boards.

The solution: You need to add the config for the nrf52840dk_n4f52840 to the MDK usb dongle but build it with the mdk usb.

I'm just shaking man. This dongle was the first one I bought and I was so disappointed in january when my first try didn't work. I couldn't even get ti to bootload and had to learn how to use the segger and nordic tools. But even with all that and the adafruit bootloader I couldn't make it work.

Now after using all the other boards, nn, xiao et al, this was the last one that was still hanging on my neck.

Thank you once again for the direction. I'll make this closed.