qmk-firmware/docs/feature_led_matrix.md

LED Matrix Lighting :id=led-matrix-lighting

This feature allows you to use LED matrices driven by external drivers. It hooks into the backlight system so you can use the same keycodes as backlighting to control it.

If you want to use RGB LED's you should use the RGB Matrix Subsystem instead.

Driver configuration :id=driver-configuration

---

IS31FL3731 :id=is31fl3731

There is basic support for addressable LED matrix lighting with the I2C IS31FL3731 LED controller. To enable it, add this to your rules.mk:

LED_MATRIX_ENABLE = yes
LED_MATRIX_DRIVER = IS31FL3731

You can use between 1 and 4 IS31FL3731 IC's. Do not specify LED_DRIVER_ADDR_<N> defines for IC's that are not present on your keyboard. You can define the following items in config.h:

Variable	Description	Default
ISSI_TIMEOUT	(Optional) How long to wait for i2c messages, in milliseconds	100
ISSI_PERSISTENCE	(Optional) Retry failed messages this many times	0
LED_DRIVER_COUNT	(Required) How many LED driver IC's are present
DRIVER_LED_TOTAL	(Required) How many LED lights are present across all drivers
LED_DRIVER_ADDR_1	(Required) Address for the first LED driver
LED_DRIVER_ADDR_2	(Optional) Address for the second LED driver
LED_DRIVER_ADDR_3	(Optional) Address for the third LED driver
LED_DRIVER_ADDR_4	(Optional) Address for the fourth LED driver

Here is an example using 2 drivers.

// This is a 7-bit address, that gets left-shifted and bit 0
// set to 0 for write, 1 for read (as per I2C protocol)
// The address will vary depending on your wiring:
// 0b1110100 AD <-> GND
// 0b1110111 AD <-> VCC
// 0b1110101 AD <-> SCL
// 0b1110110 AD <-> SDA
#define LED_DRIVER_ADDR_1 0b1110100
#define LED_DRIVER_ADDR_2 0b1110110

#define LED_DRIVER_COUNT 2
#define LED_DRIVER_1_LED_TOTAL 25
#define LED_DRIVER_2_LED_TOTAL 24
#define DRIVER_LED_TOTAL (LED_DRIVER_1_LED_TOTAL + LED_DRIVER_2_LED_TOTAL)

!> Note the parentheses, this is so when LED_DRIVER_LED_TOTAL is used in code and expanded, the values are added together before any additional math is applied to them. As an example, rand() % (LED_DRIVER_1_LED_TOTAL + LED_DRIVER_2_LED_TOTAL) will give very different results than rand() % LED_DRIVER_1_LED_TOTAL + LED_DRIVER_2_LED_TOTAL.

Define these arrays listing all the LEDs in your <keyboard>.c:

const is31_led g_is31_leds[DRIVER_LED_TOTAL] = {
/* Refer to IS31 manual for these locations
 *    driver
 *    |  LED address
 *    |  | */
    { 0, C1_1  },
    { 0, C1_15 },
    // ...
}

Where Cx_y is the location of the LED in the matrix defined by the datasheet and the header file drivers/issi/is31fl3731-simple.h. The driver is the index of the driver you defined in your config.h (0, 1, 2, or 3 ).

---

From this point forward the configuration is the same for all the drivers. The led_config_t struct provides a key electrical matrix to led index lookup table, what the physical position of each LED is on the board, and what type of key or usage the LED if the LED represents. Here is a brief example:

led_config_t g_led_config = { {
  // Key Matrix to LED Index
  {   5, NO_LED, NO_LED,   0 },
  { NO_LED, NO_LED, NO_LED, NO_LED },
  {   4, NO_LED, NO_LED,   1 },
  {   3, NO_LED, NO_LED,   2 }
}, {
  // LED Index to Physical Position
  { 188,  16 }, { 187,  48 }, { 149,  64 }, { 112,  64 }, {  37,  48 }, {  38,  16 }
}, {
  // LED Index to Flag
  1, 4, 4, 4, 4, 1
} };

The first part, // Key Matrix to LED Index, tells the system what key this LED represents by using the key's electrical matrix row & col. The second part, // LED Index to Physical Position represents the LED's physical { x, y } position on the keyboard. The default expected range of values for { x, y } is the inclusive range { 0..224, 0..64 }. This default expected range is due to effects that calculate the center of the keyboard for their animations. The easiest way to calculate these positions is imagine your keyboard is a grid, and the top left of the keyboard represents { x, y } coordinate { 0, 0 } and the bottom right of your keyboard represents { 224, 64 }. Using this as a basis, you can use the following formula to calculate the physical position:

x = 224 / (NUMBER_OF_COLS - 1) * COL_POSITION
y =  64 / (NUMBER_OF_ROWS - 1) * ROW_POSITION

Where NUMBER_OF_COLS, NUMBER_OF_ROWS, COL_POSITION, & ROW_POSITION are all based on the physical layout of your keyboard, not the electrical layout.

As mentioned earlier, the center of the keyboard by default is expected to be { 112, 32 }, but this can be changed if you want to more accurately calculate the LED's physical { x, y } positions. Keyboard designers can implement #define LED_MATRIX_CENTER { 112, 32 } in their config.h file with the new center point of the keyboard, or where they want it to be allowing more possibilities for the { x, y } values. Do note that the maximum value for x or y is 255, and the recommended maximum is 224 as this gives animations runoff room before they reset.

// LED Index to Flag is a bitmask, whether or not a certain LEDs is of a certain type. It is recommended that LEDs are set to only 1 type.

Flags :id=flags

Define	Value	Description
HAS_FLAGS(bits, flags)	n/a	Evaluates to true if bits has all flags set
HAS_ANY_FLAGS(bits, flags)	n/a	Evaluates to true if bits has any flags set
LED_FLAG_NONE	0x00	If this LED has no flags
LED_FLAG_ALL	0xFF	If this LED has all flags
LED_FLAG_MODIFIER	0x01	If the LED is on a modifier key
LED_FLAG_KEYLIGHT	0x04	If the LED is for key backlight
LED_FLAG_INDICATOR	0x08	If the LED is for keyboard state indication

Keycodes :id=keycodes

All LED matrix keycodes are currently shared with the Backlight feature.

Key	Description
BL_TOGG	Toggle LED Matrix on or off
BL_STEP	Cycle through modes
BL_ON	Turn on LED Matrix
BL_OFF	Turn off LED Matrix
BL_INC	Increase the brightness level
BL_DEC	Decrease the brightness level

LED Matrix Effects :id=led-matrix-effects

These are the effects that are currently available:

enum led_matrix_effects {
    LED_MATRIX_NONE = 0,
    LED_MATRIX_SOLID = 1,           // Static single val, no speed support
    LED_MATRIX_ALPHAS_MODS,         // Static dual val, speed is val for LEDs marked as modifiers
    LED_MATRIX_BREATHING,           // Cycling brightness animation
    LED_MATRIX_BAND,                // Band fading brightness scrolling left to right
    LED_MATRIX_BAND_PINWHEEL,       // 3 blade spinning pinwheel fades brightness
    LED_MATRIX_BAND_SPIRAL,         // Spinning spiral fades brightness
    LED_MATRIX_CYCLE_LEFT_RIGHT,    // Full gradient scrolling left to right
    LED_MATRIX_CYCLE_UP_DOWN,       // Full gradient scrolling top to bottom
    LED_MATRIX_CYCLE_OUT_IN,        // Full gradient scrolling out to in
    LED_MATRIX_DUAL_BEACON,         // Full gradient spinning around center of keyboard
#if defined(LED_MATRIX_KEYPRESSES) || defined(LED_MATRIX_KEYRELEASES)
    LED_MATRIX_SOLID_REACTIVE_SIMPLE,   // Pulses keys hit then fades out
    LED_MATRIX_SOLID_REACTIVE_WIDE       // Value pulses near a single key hit then fades out
    LED_MATRIX_SOLID_REACTIVE_MULTIWIDE  // Value pulses near multiple key hits then fades out
    LED_MATRIX_SOLID_REACTIVE_CROSS      // Value pulses the same column and row of a single key hit then fades out
    LED_MATRIX_SOLID_REACTIVE_MULTICROSS // Value pulses the same column and row of multiple key hits then fades out
    LED_MATRIX_SOLID_REACTIVE_NEXUS      // Value pulses away on the same column and row of a single key hit then fades out
    LED_MATRIX_SOLID_REACTIVE_MULTINEXUS // Value pulses away on the same column and row of multiple key hits then fades out
    LED_MATRIX_SOLID_SPLASH,             // Value pulses away from a single key hit then fades out
    LED_MATRIX_SOLID_MULTISPLASH,        // Value pulses away from multiple key hits then fades out
#endif
    LED_MATRIX_WAVE_LEFT_RIGHT           // Sine wave scrolling from left to right
    LED_MATRIX_WAVE_UP_DOWN              // Sine wave scrolling from up to down
    LED_MATRIX_EFFECT_MAX
};

You can disable a single effect by defining DISABLE_[EFFECT_NAME] in your config.h:

Define	Description
#define DISABLE_LED_MATRIX_ALPHAS_MODS	Disables LED_MATRIX_ALPHAS_MODS
#define DISABLE_LED_MATRIX_BREATHING	Disables LED_MATRIX_BREATHING
#define DISABLE_LED_MATRIX_BAND	Disables LED_MATRIX_BAND
#define DISABLE_LED_MATRIX_BAND_PINWHEEL	Disables LED_MATRIX_BAND_PINWHEEL
#define DISABLE_LED_MATRIX_BAND_SPIRAL	Disables LED_MATRIX_BAND_SPIRAL
#define DISABLE_LED_MATRIX_CYCLE_LEFT_RIGHT	Disables LED_MATRIX_CYCLE_LEFT_RIGHT
#define DISABLE_LED_MATRIX_CYCLE_UP_DOWN	Disables LED_MATRIX_CYCLE_UP_DOWN
#define DISABLE_LED_MATRIX_CYCLE_OUT_IN	Disables LED_MATRIX_CYCLE_OUT_IN
#define DISABLE_LED_MATRIX_DUAL_BEACON	Disables LED_MATRIX_DUAL_BEACON
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_SIMPLE	Disables LED_MATRIX_SOLID_REACTIVE_SIMPLE
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_WIDE	Disables LED_MATRIX_SOLID_REACTIVE_WIDE
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_MULTIWIDE	Disables LED_MATRIX_SOLID_REACTIVE_MULTIWIDE
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_CROSS	Disables LED_MATRIX_SOLID_REACTIVE_CROSS
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_MULTICROSS	Disables LED_MATRIX_SOLID_REACTIVE_MULTICROSS
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_NEXUS	Disables LED_MATRIX_SOLID_REACTIVE_NEXUS
#define DISABLE_LED_MATRIX_SOLID_REACTIVE_MULTINEXUS	Disables LED_MATRIX_SOLID_REACTIVE_MULTINEXUS
#define DISABLE_LED_MATRIX_SOLID_SPLASH	Disables LED_MATRIX_SOLID_SPLASH
#define DISABLE_LED_MATRIX_SOLID_MULTISPLASH	Disables LED_MATRIX_SOLID_MULTISPLASH
#define DISABLE_LED_MATRIX_WAVE_LEFT_RIGHT	Disables LED_MATRIX_WAVE_LEFT_RIGHT
#define DISABLE_LED_MATRIX_WAVE_UP_DOWN	Disables LED_MATRIX_WAVE_UP_DOWN

Custom LED Matrix Effects :id=custom-led-matrix-effects

By setting LED_MATRIX_CUSTOM_USER (and/or LED_MATRIX_CUSTOM_KB) in rules.mk, new effects can be defined directly from userspace, without having to edit any QMK core files.

To declare new effects, create a new led_matrix_user/kb.inc that looks something like this:

led_matrix_user.inc should go in the root of the keymap directory. led_matrix_kb.inc should go in the root of the keyboard directory.

To use custom effects in your code, simply prepend LED_MATRIX_CUSTOM_ to the effect name specified in LED_MATRIX_EFFECT(). For example, an effect declared as LED_MATRIX_EFFECT(my_cool_effect) would be referenced with:

led_matrix_mode(led_MATRIX_CUSTOM_my_cool_effect);

// !!! DO NOT ADD #pragma once !!! //

// Step 1.
// Declare custom effects using the LED_MATRIX_EFFECT macro
// (note the lack of semicolon after the macro!)
LED_MATRIX_EFFECT(my_cool_effect)
LED_MATRIX_EFFECT(my_cool_effect2)

// Step 2.
// Define effects inside the `LED_MATRIX_CUSTOM_EFFECT_IMPLS` ifdef block
#ifdef LED_MATRIX_CUSTOM_EFFECT_IMPLS

// e.g: A simple effect, self-contained within a single method
static bool my_cool_effect(effect_params_t* params) {
  LED_MATRIX_USE_LIMITS(led_min, led_max);
  for (uint8_t i = led_min; i < led_max; i++) {
    led_matrix_set_value(i, 0xFF);
  }
  return led_max < DRIVER_LED_TOTAL;
}

// e.g: A more complex effect, relying on external methods and state, with
// dedicated init and run methods
static uint8_t some_global_state;
static void my_cool_effect2_complex_init(effect_params_t* params) {
  some_global_state = 1;
}
static bool my_cool_effect2_complex_run(effect_params_t* params) {
  LED_MATRIX_USE_LIMITS(led_min, led_max);
  for (uint8_t i = led_min; i < led_max; i++) {
    led_matrix_set_value(i, some_global_state++);
  }

  return led_max < DRIVER_LED_TOTAL;
}
static bool my_cool_effect2(effect_params_t* params) {
  if (params->init) my_cool_effect2_complex_init(params);
  return my_cool_effect2_complex_run(params);
}

#endif // LED_MATRIX_CUSTOM_EFFECT_IMPLS

For inspiration and examples, check out the built-in effects under quantum/led_matrix_animations/

Additional config.h Options :id=additional-configh-options

#define LED_MATRIX_KEYPRESSES // reacts to keypresses
#define LED_MATRIX_KEYRELEASES // reacts to keyreleases (instead of keypresses)
#define LED_MATRIX_FRAMEBUFFER_EFFECTS // enable framebuffer effects
#define LED_DISABLE_TIMEOUT 0 // number of milliseconds to wait until led automatically turns off
#define LED_DISABLE_AFTER_TIMEOUT 0 // OBSOLETE: number of ticks to wait until disabling effects
#define LED_DISABLE_WHEN_USB_SUSPENDED false // turn off effects when suspended
#define LED_MATRIX_LED_PROCESS_LIMIT (DRIVER_LED_TOTAL + 4) / 5 // limits the number of LEDs to process in an animation per task run (increases keyboard responsiveness)
#define LED_MATRIX_LED_FLUSH_LIMIT 16 // limits in milliseconds how frequently an animation will update the LEDs. 16 (16ms) is equivalent to limiting to 60fps (increases keyboard responsiveness)
#define LED_MATRIX_MAXIMUM_BRIGHTNESS 255 // limits maximum brightness of LEDs
#define LED_MATRIX_STARTUP_MODE LED_MATRIX_SOLID // Sets the default mode, if none has been set
#define LED_MATRIX_STARTUP_VAL LED_MATRIX_MAXIMUM_BRIGHTNESS // Sets the default brightness value, if none has been set
#define LED_MATRIX_STARTUP_SPD 127 // Sets the default animation speed, if none has been set
#define LED_MATRIX_SPLIT { X, Y }   // (Optional) For split keyboards, the number of LEDs connected on each half. X = left, Y = Right.
                                    // If LED_MATRIX_KEYPRESSES or LED_MATRIX_KEYRELEASES is enabled, you also will want to enable SPLIT_TRANSPORT_MIRROR

EEPROM storage :id=eeprom-storage

The EEPROM for it is currently shared with the RGB Matrix system (it's generally assumed only one feature would be used at a time), but could be configured to use its own 32bit address with:

#define EECONFIG_LED_MATRIX (uint32_t *)28

Where 28 is an unused index from eeconfig.h.

Direct Operation :id=direct-operation

Function	Description
led_matrix_set_value_all(v)	Set all of the LEDs to the given value, where v is between 0 and 255 (not written to EEPROM)
led_matrix_set_value(index, v)	Set a single LED to the given value, where v is between 0 and 255, and index is between 0 and DRIVER_LED_TOTAL (not written to EEPROM)

Disable/Enable Effects :id=disable-enable-effects

Function	Description
led_matrix_toggle()	Toggle effect range LEDs between on and off
led_matrix_toggle_noeeprom()	Toggle effect range LEDs between on and off (not written to EEPROM)
led_matrix_enable()	Turn effect range LEDs on, based on their previous state
led_matrix_enable_noeeprom()	Turn effect range LEDs on, based on their previous state (not written to EEPROM)
led_matrix_disable()	Turn effect range LEDs off, based on their previous state
led_matrix_disable_noeeprom()	Turn effect range LEDs off, based on their previous state (not written to EEPROM)

Change Effect Mode :id=change-effect-mode

Function	Description
led_matrix_mode(mode)	Set the mode, if LED animations are enabled
led_matrix_mode_noeeprom(mode)	Set the mode, if LED animations are enabled (not written to EEPROM)
led_matrix_step()	Change the mode to the next LED animation in the list of enabled LED animations
led_matrix_step_noeeprom()	Change the mode to the next LED animation in the list of enabled LED animations (not written to EEPROM)
led_matrix_step_reverse()	Change the mode to the previous LED animation in the list of enabled LED animations
led_matrix_step_reverse_noeeprom()	Change the mode to the previous LED animation in the list of enabled LED animations (not written to EEPROM)
led_matrix_increase_speed()	Increase the speed of the animations
led_matrix_increase_speed_noeeprom()	Increase the speed of the animations (not written to EEPROM)
led_matrix_decrease_speed()	Decrease the speed of the animations
led_matrix_decrease_speed_noeeprom()	Decrease the speed of the animations (not written to EEPROM)
led_matrix_set_speed(speed)	Set the speed of the animations to the given value where speed is between 0 and 255
led_matrix_set_speed_noeeprom(speed)	Set the speed of the animations to the given value where speed is between 0 and 255 (not written to EEPROM)

Change Value :id=change-value

Function	Description
led_matrix_increase_val()	Increase the value for effect range LEDs. This wraps around at maximum value
led_matrix_increase_val_noeeprom()	Increase the value for effect range LEDs. This wraps around at maximum value (not written to EEPROM)
led_matrix_decrease_val()	Decrease the value for effect range LEDs. This wraps around at minimum value
led_matrix_decrease_val_noeeprom()	Decrease the value for effect range LEDs. This wraps around at minimum value (not written to EEPROM)

Query Current Status :id=query-current-status

Function	Description
led_matrix_is_enabled()	Gets current on/off status
led_matrix_get_mode()	Gets current mode
led_matrix_get_val()	Gets current val
led_matrix_get_speed()	Gets current speed
led_matrix_get_suspend_state()	Gets current suspend state

Callbacks :id=callbacks

Indicators :id=indicators

If you want to set custom indicators, such as an LED for Caps Lock, or layer indication, you can use the led_matrix_indicators_kb or led_matrix_indicators_user function for that:

void led_matrix_indicators_kb(void) {
    led_matrix_set_color(index, value);
}

In addition, there are the advanced indicator functions. These are aimed at those with heavily customized displays, where rendering every LED per cycle is expensive. This includes a special macro to help make this easier to use: LED_MATRIX_INDICATOR_SET_VALUE(i, v).

void led_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
    LED_MATRIX_INDICATOR_SET_VALUE(index, value);
}

Suspended State :id=suspended-state

To use the suspend feature, make sure that #define LED_DISABLE_WHEN_USB_SUSPENDED true is added to the config.h file.

Additionally add this to your <keyboard>.c:

void suspend_power_down_kb(void) {
    led_matrix_set_suspend_state(true);
    suspend_power_down_user();
}

void suspend_wakeup_init_kb(void) {
    led_matrix_set_suspend_state(false);
    suspend_wakeup_init_user();
}

or add this to your keymap.c:

void suspend_power_down_user(void) {
    led_matrix_set_suspend_state(true);
}

void suspend_wakeup_init_user(void) {
    led_matrix_set_suspend_state(false);
}