@ -8,11 +8,11 @@ title: Boards, Shields, and Keymaps
The foundational elements needed to get a specific keyboard working with ZMK can be broken down into:
The foundational elements needed to get a specific keyboard working with ZMK can be broken down into:
- A [KSCAN driver](https://docs.zephyrproject.org/2.3.0/reference/peripherals/kscan.html), which uses `compatible="zmk,kscan-gpio-matrix"` for GPIO matrix based keyboards, or uses `compatible="zmk,kscan-gpio-direct"` for small direct wires.
- A [KSCAN driver](https://docs.zephyrproject.org/2.3.0/reference/peripherals/kscan.html), which uses `compatible="zmk,kscan-gpio-matrix"` for GPIO matrix based keyboards, or uses `compatible="zmk,kscan-gpio-direct"` for small direct wires.
- An optional matrix transform, which defines how the KSCAN row/column events are translated into logical "key positions". This is required for non-rectangular keyboards/matrixes, where the key positions don't naturally follow the row/columns from the GPIO matrix.
- An optional matrix transform, which defines how the KSCAN row/column events are translated into logical "key positions". This is required for non-rectangular keyboards/matrices, where the key positions don't naturally follow the row/columns from the GPIO matrix.
- A keymap, which binds each key position to a behavior, e.g. key press, mod-tap, momentary layer, in a set of layers.
- A keymap, which binds each key position to a behavior, e.g. key press, mod-tap, momentary layer, in a set of layers.
These three core architectural elements are defined per-keyboard, and _where_ they are defined depeneds on the specifics of how that
These three core architectural elements are defined per-keyboard, and _where_ they are defined depends on the specifics of how that
keyboard works. For an overview on the general concepts of boards and shields, please see the [FAQs on boards and sheilds](/docs/faq#why-boards-and-shields--why-not-just-keyboard).
keyboard works. For an overview on the general concepts of boards and shields, please see the [FAQs on boards and shields](/docs/faq#why-boards-and-shields--why-not-just-keyboard).
- Add the shield overlay file to define the [KSCAN driver]() for detecting key press/release.
- Add the shield overlay file to define the [KSCAN driver]() for detecting key press/release.
- (Optional) Add the mateix transform for mapping KSCAN row/coluk values to sane key positions. This is needed for non-rectangular keyboards, or where the underlying row/column pin arrangement does not map one to one with logical locations on the keyboard.
- (Optional) Add the matrix transform for mapping KSCAN row/column values to sane key positions. This is needed for non-rectangular keyboards, or where the underlying row/column pin arrangement does not map one to one with logical locations on the keyboard.
- Add a default keymap, which users can override in their own configs as needed.
- Add a default keymap, which users can override in their own configs as needed.
It may be helpful to review the upstream [shields documentation](https://docs.zephyrproject.org/2.3.0/guides/porting/shields.html#shields) to get a proper understanding of the underlying system before continuing.
It may be helpful to review the upstream [shields documentation](https://docs.zephyrproject.org/2.3.0/guides/porting/shields.html#shields) to get a proper understanding of the underlying system before continuing.
## New Shield Directory
## New Shield Directory
Shields for Zephyr applications go into the `boards/shields/` directory; since ZMK's Zephyr appliction linves in the `app/` subdirectory of the repository, that means the new shield directory should be:
Shields for Zephyr applications go into the `boards/shields/` directory; since ZMK's Zephyr application lives in the `app/` subdirectory of the repository, that means the new shield directory should be:
```bash
```bash
mkdir app/boards/shields/<keyboard_name>
mkdir app/boards/shields/<keyboard_name>
@ -60,7 +60,7 @@ endif
## Shield Overlay
## Shield Overlay
The `<shield_name>.overlay` is the devicetree description of the keyboard shield that is merged with the primary board devicetree description before the build. For ZMK, this file at a minumum should include the [chosen]() node named `zmk,kscan` that refernces a KSCAN driver instance. For a simple 3x3 macropad matrix,
The `<shield_name>.overlay` is the devicetree description of the keyboard shield that is merged with the primary board devicetree description before the build. For ZMK, this file at a minimum should include the [chosen]() node named `zmk,kscan` that references a KSCAN driver instance. For a simple 3x3 macropad matrix,
this might look something like:
this might look something like:
```
```
@ -97,7 +97,7 @@ Internally ZMK translates all row/column events into "key position" events to ma
1. For non rectangular keyboards with thumb clusters, non `1u` locations, etc.
1. For non rectangular keyboards with thumb clusters, non `1u` locations, etc.
A "key position" is the numeric index (zero-based) of a given key, which identifies
A "key position" is the numeric index (zero-based) of a given key, which identifies
the logical key location as percieved by the end user. All _keymap_ mappings actually bind behaviors to _key positions_, not to row/column values.
the logical key location as perceived by the end user. All _keymap_ mappings actually bind behaviors to _key positions_, not to row/column values.
_Without_ a matrix transform, that intentionally map each key position to the row/column pair that position corresponds to, the default equation to determine that is:
_Without_ a matrix transform, that intentionally map each key position to the row/column pair that position corresponds to, the default equation to determine that is:
- The `#include <dt-bindings/zmk/matrix-transform.h>` is critical. The `RC` macro is used to generate the interanl storage in the matrix transform, and is actually replaced by a C preprocessor before the final devicetree is compiled into ZMK.
- The `#include <dt-bindings/zmk/matrix-transform.h>` is critical. The `RC` macro is used to generate the internal storage in the matrix transform, and is actually replaced by a C preprocessor before the final devicetree is compiled into ZMK.
- `RC(row, column)` is placed sequentially to define what row and column values that position corresponds to.
- `RC(row, column)` is placed sequentially to define what row and column values that position corresponds to.
- If you have a keyboard with options for `2u` keys in certain positions, or break away portions, it is a good idea to set the chosen `zmk,matrix_transform` to the default arrangement, and include _other_ possible matrix transform nodes in the devicetree that users can select in their user config by overriding the chosen node.
- If you have a keyboard with options for `2u` keys in certain positions, or break away portions, it is a good idea to set the chosen `zmk,matrix_transform` to the default arrangement, and include _other_ possible matrix transform nodes in the devicetree that users can select in their user config by overriding the chosen node.
## Default Keymap
## Default Keymap
Each keyboard should provide an OOTB default keymap to be used when building the firmware, which can be overriden and customized by user configs. For "shield keyboards", this should be placed in the `app/boards/shields/<shield_name>/keymap/keymap.overlay` file. The keymap is configured as an additional devicetree overlay that includes the following:
Each keyboard should provide an OOTB default keymap to be used when building the firmware, which can be overridden and customized by user configs. For "shield keyboards", this should be placed in the `app/boards/shields/<shield_name>/keymap/keymap.overlay` file. The keymap is configured as an additional devicetree overlay that includes the following:
- A node with `compatible="zmk,layers"` where each child node is a layer with a `bindings` array that binds each key position to a given behavior (e.g. key press, momentarily layer, etc).
- A node with `compatible="zmk,layers"` where each child node is a layer with a `bindings` array that binds each key position to a given behavior (e.g. key press, momentarily layer, etc).
- A node with `compatible="zmk,keymap"` that references the layers with a `layers` phandle-array property.
- A node with `compatible="zmk,keymap"` that references the layers with a `layers` phandle-array property.
@ -10,7 +10,7 @@ flowing into the handler functions.
## Prerequisites
## Prerequisites
In order to build targetting the `native_posix` board, you need to setup your system
In order to build targeting the `native_posix` board, you need to setup your system
with a compiler that can target 32-bit POSIX.
with a compiler that can target 32-bit POSIX.
On Debian, you can do this with:
On Debian, you can do this with:
@ -21,7 +21,7 @@ apt install -y gcc-multilib
## Building
## Building
To do this, you can build ZMK targetting the
To do this, you can build ZMK targeting the
`native_posix` board.
`native_posix` board.
```
```
@ -36,4 +36,4 @@ Once built, you can run the firmware locally:
## Virtual Key Events
## Virtual Key Events
The virtual key presses are hardcoded in `boards/native_posix.overlay` file. should you want to change the sequence to test various actions like Mod-Tap, etc.
The virtual key presses are hardcoded in `boards/native_posix.overlay` file, should you want to change the sequence to test various actions like Mod-Tap, etc.
The installation will prompt with several questions about installation location, and creating a default `~/.zephyrrc` for you with various variables. The defaults shouldn normally work as expected.
The installation will prompt with several questions about installation location, and creating a default `~/.zephyrrc` for you with various variables. The defaults should normally work as expected.
The installation will prompt with several questions about installation location, and creating a default `~/.zephyrrc` for you with various variables. The defaults shouldn normally work as expected.
The installation will prompt with several questions about installation location, and creating a default `~/.zephyrrc` for you with various variables. The defaults should normally work as expected.
The installation will prompt with several questions about installation location, and creating a default `~/.zephyrrc` for you with various variables. The defaults shouldn normally work as expected.
The installation will prompt with several questions about installation location, and creating a default `~/.zephyrrc` for you with various variables. The defaults should normally work as expected.
</TabItem>
</TabItem>
</OsTabs>
</OsTabs>
:::note
If you intend to build firmware straight away, make sure to correctly setup the current shell.
Notes on setting this up can be found in the [Environment Variables](#environment-variables) section.
The transient instructions can be used to setup the current shell, and the automatic instructions can setup any newly made shells automatically.
The transient instructions must be run to build firmware using the current shell.
:::
### Source Code
### Source Code
Next, you'll need to clone the ZMK source repository if you haven't already:
Next, you'll need to clone the ZMK source repository if you haven't already:
Pete Johanson
4 years ago
committed by