This repository outlines most of the steps needed to build/modify the ZMK firmware for a Wireless Charybdis keyboard.
If you'd like to skip all the configuration steps and use something prebuilt, the firmware files can be found in the Actions Workflows. Just click the link, select the latest run that passed on the main branch, and download the firmware-charybdis-nanov2-qwerty artifact (there's also a colemak dh firmware for those few that want to use that layout). You'll have to be logged into Github for this.
There are a few things to note about how I've chosen to configure things.
- The keyboard name is Charybdis. This is what will show up when you connect to it with bluetooth.
- ZMK has terms for each side of a split keyboard. Central is the half that sends keyboard outputs over USB or advertises to other devices over bluetooth. Peripheral is the half that will only send keystrokes to the central once they are paired and connected through bluetooth. These builds use the right side as central.
- To add support for the PMW3610 sensor, inorichi's driver is included in the firmware.
- Petejohanson's work is also included in the build to allow mouse keys to work. This will be included until ZMK merges it.
Each layer has been heavily influanced by Miryoku and home row mods that use bilateral combinations to make typing as efficient and comfortable as possible. Extra attention has also been given to making sure cursor, scrolling, and mouse button opperations are as seemless and available as possible. This removes the need to ever remove your hands from the keyboard home row.
Review the layer maps below to see how each one functions. Then connect the keyboard via USB or bluetooth and start using them.
Here are a few hints for a quick start:
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When moving the trackball, the mouse layer will be automatically activated. When the trackball movement stops, the previous layer is activated again.
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The bluetooth keys on the EXTRAS layer allow you to select which bluetooth pairing you want, BT-CLR clears the pairing on the selected profile.
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The most left thumb button has multiple functions
- When held, the function of the trackball is changed from moving the cursor to scrolling.
- When double tapped, it will reduce the cursor speed for more precision, and activate the mouse layer.
- When single tapped it will activate the base layer.
Before adding/updating a keymap, you need to select a behavior, then choose a parameter code that you plan to update the key to. This process is more clearly outlined on ZMK's Keymaps & Behaviors page.
- Behaviors are all documented on the Behaviors Overview
- Codes are all documented on the keycodes page
There are a few options available to update the keymaps with the chosen behavior and code.
You can edit the keymap file directly to match any configuration you want by using the behavior and codes from above.
Using a GUI to generate the keymap file content is the easiest option. Head over to nickcoutsos' keymap editor and follow the steps below.
- Fork this repo
- Open a new tab to the keymap editor
- Give it permission to your fork
- Select the branch you'd like to modify
- Update the keys to match what you'd like to use on your keyboard
- Save
- Wait for the pipeline to run
- Download and flash the new firmware
- Unzip the firmware.zip
- Plug the right half info the computer through USB
- Double press the reset button
- The keyboard will mount as a removable storage device
- Copy the right side uf2 file into the NICENANO storage device.
- It will take a few seconds, then it will unmount and restart itself.
- Plug in the left half, and copy the left uf2 file.
- Both halves of the keyboard should now be flashed with the firmware.
ZMK provides a comprehensive guide to follow when creating a New Keyboard Shield. I'll touch on some of the points here, but their docs should be what you reference when you're building your own firmware.
The file locations for setting up the repo to build the firmware matters. The formats and locations of the files can be found on ZMK's Configuration Overview. One thing to note about this repo is that the keymap and json files are in the config directory to work with a GUI keymapper. Also, the matrix-transform is included as part of the charbdis.dtsi file.
To set up some of the configuration files it requires a knowledge of which keys connect to which pins on the MCU (see the Shield Overlays section), and how the rows and columns are wired.
To get this information, look at the PCB kcad files and follow the traces from key pads, to row and column through holes, to MCU through holes. Once you have that information you can update the shield.dtsi, shield_left.overlay, and shield_right.overlay files.
Follow the ZMK documentation to change the Kconfig.deconfig.
Follow the ZMK Kconfig.defconfig section to update the keyboard name. Make sure to read about the danger in exceeding the 16 character limit.
This repo uses the excellent work of caksoylar's Keymap Drawer to automatically generate a key mapping of each layer when the Github Actions are run.
ZMK is actively being developed and there are a few features I'll be adding to my builds as soon as they are released.
- Mouse Pointer & Scrolling - PR in review
- Layer Locks - Layer locks will hopefully get merged in