- # Joystick :id=joystick
-
- This feature provides game controller input as a joystick device supporting up to 6 axes and 32 buttons. Axes can be read either from an [ADC-capable input pin](adc_driver.md), or can be virtual, so that its value is provided by your code.
-
- An analog device such as a [potentiometer](https://en.wikipedia.org/wiki/Potentiometer) found on an analog joystick's axes is based on a voltage divider, where adjusting the movable wiper controls the output voltage which can then be read by the microcontroller's ADC.
-
- ## Usage :id=usage
-
- Add the following to your `rules.mk`:
-
- ```make
- JOYSTICK_ENABLE = yes
- ```
-
- By default the joystick driver is `analog`, but you can change this with:
-
- ```make
- JOYSTICK_DRIVER = digital
- ```
-
- ## Configuration :id=configuration
-
- By default, two axes and eight buttons are defined, with a reported resolution of 8 bits (-127 to +127). This can be changed in your `config.h`:
-
- ```c
- // Min 0, max 32
- #define JOYSTICK_BUTTON_COUNT 16
- // Min 0, max 6: X, Y, Z, Rx, Ry, Rz
- #define JOYSTICK_AXIS_COUNT 3
- // Min 8, max 16
- #define JOYSTICK_AXIS_RESOLUTION 10
- ```
-
- ?> You must define at least one button or axis. Also note that the maximum ADC resolution of the supported AVR MCUs is 10-bit, and 12-bit for most STM32 MCUs.
-
- ### Axes :id=axes
-
- When defining axes for your joystick, you must provide a definition array typically in your `keymap.c`.
-
- For instance, the below example configures two axes. The X axis is read from the `A4` pin. With the default axis resolution of 8 bits, the range of values between 900 and 575 are scaled to -127 through 0, and values 575 to 285 are scaled to 0 through 127. The Y axis is configured as a virtual axis, and its value is not read from any pin. Instead, the user must update the axis value programmatically.
-
- ```c
- joystick_config_t joystick_axes[JOYSTICK_AXIS_COUNT] = {
- JOYSTICK_AXIS_IN(A4, 900, 575, 285),
- JOYSTICK_AXIS_VIRTUAL
- };
- ```
-
- Axes can be configured using one of the following macros:
-
- * `JOYSTICK_AXIS_IN(input_pin, low, rest, high)`
- The ADC samples the provided pin. `low`, `high` and `rest` correspond to the minimum, maximum, and resting (or centered) analog values of the axis, respectively.
- * `JOYSTICK_AXIS_VIRTUAL`
- No ADC reading is performed. The value should be provided by user code.
-
- The `low` and `high` values can be swapped to effectively invert the axis.
-
- #### Virtual Axes :id=virtual-axes
-
- The following example adjusts two virtual axes (X and Y) based on keypad presses, with `KC_P0` as a precision modifier:
-
- ```c
- joystick_config_t joystick_axes[JOYSTICK_AXIS_COUNT] = {
- JOYSTICK_AXIS_VIRTUAL, // x
- JOYSTICK_AXIS_VIRTUAL // y
- };
-
- static bool precision = false;
- static uint16_t precision_mod = 64;
- static uint16_t axis_val = 127;
-
- bool process_record_user(uint16_t keycode, keyrecord_t *record) {
- int16_t precision_val = axis_val;
- if (precision) {
- precision_val -= precision_mod;
- }
-
- switch (keycode) {
- case KC_P8:
- joystick_set_axis(1, record->event.pressed ? -precision_val : 0);
- return false;
- case KC_P2:
- joystick_set_axis(1, record->event.pressed ? precision_val : 0);
- return false;
- case KC_P4:
- joystick_set_axis(0, record->event.pressed ? -precision_val : 0);
- return false;
- case KC_P6:
- joystick_set_axis(0, record->event.pressed ? precision_val : 0);
- return false;
- case KC_P0:
- precision = record->event.pressed;
- return false;
- }
- return true;
- }
- ```
-
- ## Keycodes :id=keycodes
-
- |Key |Aliases|Description|
- |-----------------------|-------|-----------|
- |`QK_JOYSTICK_BUTTON_0` |`JS_0` |Button 0 |
- |`QK_JOYSTICK_BUTTON_1` |`JS_1` |Button 1 |
- |`QK_JOYSTICK_BUTTON_2` |`JS_2` |Button 2 |
- |`QK_JOYSTICK_BUTTON_3` |`JS_3` |Button 3 |
- |`QK_JOYSTICK_BUTTON_4` |`JS_4` |Button 4 |
- |`QK_JOYSTICK_BUTTON_5` |`JS_5` |Button 5 |
- |`QK_JOYSTICK_BUTTON_6` |`JS_6` |Button 6 |
- |`QK_JOYSTICK_BUTTON_7` |`JS_7` |Button 7 |
- |`QK_JOYSTICK_BUTTON_8` |`JS_8` |Button 8 |
- |`QK_JOYSTICK_BUTTON_9` |`JS_9` |Button 9 |
- |`QK_JOYSTICK_BUTTON_10`|`JS_10`|Button 10 |
- |`QK_JOYSTICK_BUTTON_11`|`JS_11`|Button 11 |
- |`QK_JOYSTICK_BUTTON_12`|`JS_12`|Button 12 |
- |`QK_JOYSTICK_BUTTON_13`|`JS_13`|Button 13 |
- |`QK_JOYSTICK_BUTTON_14`|`JS_14`|Button 14 |
- |`QK_JOYSTICK_BUTTON_15`|`JS_15`|Button 15 |
- |`QK_JOYSTICK_BUTTON_16`|`JS_16`|Button 16 |
- |`QK_JOYSTICK_BUTTON_17`|`JS_17`|Button 17 |
- |`QK_JOYSTICK_BUTTON_18`|`JS_18`|Button 18 |
- |`QK_JOYSTICK_BUTTON_19`|`JS_19`|Button 19 |
- |`QK_JOYSTICK_BUTTON_20`|`JS_20`|Button 20 |
- |`QK_JOYSTICK_BUTTON_21`|`JS_21`|Button 21 |
- |`QK_JOYSTICK_BUTTON_22`|`JS_22`|Button 22 |
- |`QK_JOYSTICK_BUTTON_23`|`JS_23`|Button 23 |
- |`QK_JOYSTICK_BUTTON_24`|`JS_24`|Button 24 |
- |`QK_JOYSTICK_BUTTON_25`|`JS_25`|Button 25 |
- |`QK_JOYSTICK_BUTTON_26`|`JS_26`|Button 26 |
- |`QK_JOYSTICK_BUTTON_27`|`JS_27`|Button 27 |
- |`QK_JOYSTICK_BUTTON_28`|`JS_28`|Button 28 |
- |`QK_JOYSTICK_BUTTON_29`|`JS_29`|Button 29 |
- |`QK_JOYSTICK_BUTTON_30`|`JS_30`|Button 30 |
- |`QK_JOYSTICK_BUTTON_31`|`JS_31`|Button 31 |
-
- ## API :id=api
-
- ### `struct joystick_t` :id=api-joystick-t
-
- Contains the state of the joystick.
-
- #### Members :id=api-joystick-t-members
-
- - `uint8_t buttons[]`
- A bit-packed array containing the joystick button states. The size is calculated as `(JOYSTICK_BUTTON_COUNT - 1) / 8 + 1`.
- - `int16_t axes[]`
- An array of analog values for each defined axis.
- - `bool dirty`
- Whether the current state needs to be sent to the host.
-
- ---
-
- ### `struct joystick_config_t` :id=api-joystick-config-t
-
- Describes a single axis.
-
- #### Members :id=api-joystick-config-t-members
-
- - `pin_t input_pin`
- The pin to read the analog value from, or `JS_VIRTUAL_AXIS`.
- - `uint16_t min_digit`
- The minimum analog value.
- - `uint16_t mid_digit`
- The resting or midpoint analog value.
- - `uint16_t max_digit`
- The maximum analog value.
-
- ---
-
- ### `void joystick_flush(void)` :id=api-joystick-flush
-
- Send the joystick report to the host, if it has been marked as dirty.
-
- ---
-
- ### `void register_joystick_button(uint8_t button)` :id=api-register-joystick-button
-
- Set the state of a button, and flush the report.
-
- #### Arguments :id=api-register-joystick-button-arguments
-
- - `uint8_t button`
- The index of the button to press, from 0 to 31.
-
- ---
-
- ### `void unregister_joystick_button(uint8_t button)` :id=api-unregister-joystick-button
-
- Reset the state of a button, and flush the report.
-
- #### Arguments :id=api-unregister-joystick-button-arguments
-
- - `uint8_t button`
- The index of the button to release, from 0 to 31.
-
- ---
-
- ### `int16_t joystick_read_axis(uint8_t axis)` :id=api-joystick-read-axis
-
- Sample and process the analog value of the given axis.
-
- #### Arguments :id=api-joystick-read-axis-arguments
-
- - `uint8_t axis`
- The axis to read.
-
- #### Return Value :id=api-joystick-read-axis-return
-
- A signed 16-bit integer, where 0 is the resting or mid point.
-
- ### `void joystick_set_axis(uint8_t axis, int16_t value)` :id=api-joystick-set-axis
-
- Set the value of the given axis.
-
- #### Arguments :id=api-joystick-set-axis-arguments
-
- - `uint8_t axis`
- The axis to set the value of.
- - `int16_t value`
- The value to set.
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