ZMK - rittme/nrfmicro GitHub Wiki

Modern, open source Zephyr-based wireless keyboard firmware. Probaby the best choice for now. Also see QMK.

Repositories

Building

Note that nRFMicro and Jorne are officially supported now. Read official documentation here:

Build

(Before calling west, set up Zephyr environment, as here https://zmkfirmware.dev/docs/development/setup)

Building jorne (looks like nrfmicro is still not in the build.yml so you'd have to use command line):

git clone https://github.com/joric/zmk
cd zmk && git checkout jorne
west build -p -b nrfmicro_13 -- -DSHIELD=jorne_left
west build -p -b nrfmicro_13 -- -DSHIELD=jorne_right

Power profiler

See https://github.com/joric/nrfmicro/wiki/Batteries#zmk

Jorne keyboard

I built ZMK firmware for my Jorne keyboard. You may download binares and code.

ZMK-Config

This is the latest ZMK (clone the repo to rebuild and download artifacts, or get firmware.zip from releases):

Keymap editor (fork the repository above and use it on your fork):

Jorne branch

This is really outdated and includes patches that are already in the mainstream ZMK but you can peek RGB configuration here.

Direct links to the latest release with RGB sync (this is for nRFMicro 1.3+, double press reset and upload .uf2 to disk as usual):

You may also need erasing the flash to reset bonds if nothing else helps:

Direct link to releases section:

This firmware supports OLED screens, per-key RGB leds and VCC power saving.

Code

Patches

I had to merge a few patches into my base repository, some are already merged to upstream (follow zmk github)

Shortcuts

RGBTOG currently toggles VCC as well (CONFIG_ZMK_RGB_UNDERGLOW_EXT_POWER=y). There's no sleep mode or lock shortcuts in ZMK just yet, sleep mode as automatic (15 minutes).

  • Raise + Lower + ~ Turn RGB and OLED off (essentially turns off VCC, key matrix still works)
  • Raise + Lower + Shift Reset Bluetooth bonds

See full keymap here:

Issues

  • VCC management seems fine with the latest ZMK, no leak, checked with 26 LEDs per each half, but it needs manual turning off with a shortcut (currently it's tied to RGBTOG). Key matrix still works even with VCC off, it only turns off OLED and RGB.
  • OLED initialization is static in Zephyr so it only works if VCC is enabled on startup. To check if OLEDs work, enable RGB+VCC using RGBTOG key binding, then wait at least a minute. After that, that'd be stored to settings and restored at startup/reset (fixed in #674, #675 so you may want to pull fresh ZMK)

Video

Misc

E-ink

Trackpoint

See my article about trackpoints: https://github.com/joric/jorne/wiki/Trackpoint There are currently 2 problems:

  1. nobody tried trackpoint at 3.3v (edit: tried, it works)
  2. all trackpoints are ps/2 and there's no ps/2 support in ZMK (there's ps/2 driver in zephyr though)

TL;DR: trackpoints work with ps/2 Arduino library at 3.3V just fine. There's no ZMK support just yet.

nRF52833

Instructions on how to configure ZMK to work with nrf52833.

Taken from https://github.com/ci-bus/zmk-nrf52833, also see https://github.com/zmkfirmware/zmk/pull/912.

Let's first see some differences between E73 2G4M08SIE (nrf52833) and E73 2G4M08S1C (nrf52840)

E73 2G4M08S1C (nrf52840) E73 2G4M08SIE (nrf52833)
Memory 1024 kB 512 kB
RAM 256 kB 128 kB
Pin 1 P1.11 Not connected
Pin 25 DCCH Not connected
DC / DC output Yes No
SD Yes Insufficient memory
Partitions nrf52840 nrf52833
SD / MBR partition 152kB 4kB
CODE partition 792kB 428kB
Storage partition 32kB 32kB
Boot partition 48kB 48kB

Loading the bootloader

  1. Flash the pca10100_bootloader-0.6.2_s140_6.1.1.hex file from this repository
  2. Connected by USB it should appear as a memory or pendrive, copy the file update-pca10100_bootloader-0.6.2_nosd.uf2

Since with nrf52833 we only have 428kB available it will not be possible to have a screen, or if you have one it must be with a very limited code, the basic zmk code for a 60% keyboard with two layers working via usb and bluetooth needs 312kB, if a that we add the functionality of rgb underglow rises to 328kB

Configuring ZMK

Let's see what configurations to do, these examples are based on a board arm like nice_nano or nrfmicro

  1. Change the SOC settings in the ** _ config.c ** file
CONFIG_SOC_NRF52833_QIAA = y
  1. Change base dtsi import and definition of partitions in the **. Dts ** file
#include <nordic / nrf52833_qiaa.dtsi>

& flash0 {
  partitions {
    compatible = "fixed-partitions";
    # address-cells = <1>;
    # size-cells = <1>;

    sd_partition: partition @ 0 {
      label = "mbr";
      reg = <0x00000000 0x00001000>;
    };

    code_partition: partition @ 1000 {
      label = "code_partition";
      reg = <0x00001000 0x0006b000>;
    };

    storage_partition: partition @ 6c000 {
      label = "storage";
      reg = <0x0006c000 0x00008000>;
    };

    boot_partition: partition @ 74000 {
      label = "adafruit_boot";
      reg = <0x00074000 0x0000c000>;
    };
  };
};
  1. Change in the ** CMakeLists.txt ** file the position where you start writing the code
  -b 0x1000

With these changes we can now enjoy ZMK on our nrf52833 chip

The bootloader comes from the adafruit repo, to flash the micro you must press reset twice very quickly that will make it appear as a pendrive, then copy the .uf2 file generated by ZMK.

Alternative bootloaders

There are also nRFMicro-customized bootloaders (nRF52833 only, for 2G4M08S1E modules):

Displays seem to work with the latest ZMK, and there's apparently some program space left for RGB as well.

nrf52833-displays

Memory region         Used Size  Region Size  %age Used
           FLASH:      265184 B       280 KB     92.49%
            SRAM:       55791 B       128 KB     42.57%
        IDT_LIST:          0 GB         2 KB      0.00%

There is no feature set in which the 833 bests the 840, but E73-C is just not available anymore, and E73-E is the same price now that the E73-C was before so there's basically no practical benefit to the 840.

ZMK hardware design guide

Super cool guide by @ebastier (features Holyiot 18010 and overdischarge protection for 18650s)

References

⚠️ **GitHub.com Fallback** ⚠️