espressif/led_strip

readme

# LED Strip Driver

[![Component Registry](https://components.espressif.com/components/espressif/led_strip/badge.svg)](https://components.espressif.com/components/espressif/led_strip)

This driver is designed for addressable LEDs like [WS2812](http://www.world-semi.com/Certifications/WS2812B.html), where each LED is controlled by a single data line.

## Backend Controllers

### The [RMT](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/rmt.html) Peripheral

This is the most economical way to drive the LEDs because it only consumes one RMT channel, leaving other channels free to use. However, the memory usage increases dramatically with the number of LEDs. If the RMT hardware can't be assist by DMA, the driver will going into interrupt very frequently, thus result in a high CPU usage. What's worse, if the RMT interrupt is delayed or not serviced in time (e.g. if Wi-Fi interrupt happens on the same CPU core), the RMT transaction will be corrupted and the LEDs will display incorrect colors. If you want to use RMT to drive a large number of LEDs, you'd better to enable the DMA feature if possible [^1].

#### Allocate LED Strip Object with RMT Backend

```c
#define BLINK_GPIO 0

/// LED strip common configuration
led_strip_config_t strip_config = {
    .strip_gpio_num = BLINK_GPIO,  // The GPIO that connected to the LED strip's data line
    .max_leds = 1,                 // The number of LEDs in the strip,
    .led_model = LED_MODEL_WS2812, // LED strip model, it determines the bit timing
    .color_component_format = LED_STRIP_COLOR_COMPONENT_FMT_GRB, // The color component format is G-R-B
    .flags = {
        .invert_out = false, // don't invert the output signal
    }
};

/// RMT backend specific configuration
led_strip_rmt_config_t rmt_config = {
    .clk_src = RMT_CLK_SRC_DEFAULT,    // different clock source can lead to different power consumption
    .resolution_hz = 10 * 1000 * 1000, // RMT counter clock frequency: 10MHz
    .mem_block_symbols = 64,           // the memory size of each RMT channel, in words (4 bytes)
    .flags = {
        .with_dma = false, // DMA feature is available on chips like ESP32-S3/P4
    }
};

/// Create the LED strip object
led_strip_handle_t led_strip;
ESP_ERROR_CHECK(led_strip_new_rmt_device(&strip_config, &rmt_config, &led_strip));
```

You can create multiple LED strip objects with different GPIOs and pixel numbers. The backend driver will automatically allocate the RMT channel for you if there is more available.

### The [SPI](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/spi_master.html) Peripheral

SPI peripheral can also be used to generate the timing required by the LED strip. However this backend is not as economical as the RMT one, because it will take up the whole **bus**, unlike the RMT just takes one **channel**. You **CANT** connect other devices to the same SPI bus if it's been used by the led_strip, because the led_strip doesn't have the concept of "Chip Select".

Please note, the SPI backend has a dependency of **ESP-IDF >= 5.1**

#### Allocate LED Strip Object with SPI Backend

```c
#define BLINK_GPIO 0

/// LED strip common configuration
led_strip_config_t strip_config = {
    .strip_gpio_num = BLINK_GPIO,  // The GPIO that connected to the LED strip's data line
    .max_leds = 1,                 // The number of LEDs in the strip,
    .led_model = LED_MODEL_WS2812, // LED strip model, it determines the bit timing
    .color_component_format = LED_STRIP_COLOR_COMPONENT_FMT_GRB, // The color component format is G-R-B
    .flags = {
        .invert_out = false, // don't invert the output signal
    }
};

/// SPI backend specific configuration
led_strip_spi_config_t spi_config = {
    .clk_src = SPI_CLK_SRC_DEFAULT, // different clock source can lead to different power consumption
    .spi_bus = SPI2_HOST,           // SPI bus ID
    .flags = {
        .with_dma = true, // Using DMA can improve performance and help drive more LEDs
    }
};

/// Create the LED strip object
led_strip_handle_t led_strip;
ESP_ERROR_CHECK(led_strip_new_spi_device(&strip_config, &spi_config, &led_strip));
```

The number of LED strip objects can be created depends on how many free SPI buses are free to use in your project.

## FAQ

* Which led_strip backend should I choose?
  * It depends on your application requirement and target chip's ability.

    ```mermaid
    flowchart LR
    A{Is RMT supported?}
    A --> |No| B[SPI backend]
    B --> C{Does the led strip has \n a larger number of LEDs?}
    C --> |No| D[Don't have to enable the DMA of the backend]
    C --> |Yes| E[Enable the DMA of the backend]
    A --> |Yes| F{Does the led strip has \n a larger number of LEDs?}
    F --> |Yes| G{Does RMT support DMA?}
    G --> |Yes| E
    G --> |No| B
    F --> |No| H[RMT backend] --> D
    ```

* How to set the brightness of the LED strip?
  * You can tune the brightness by scaling the value of each R-G-B element with a **same** factor. But pay attention to the overflow of the value.

[^1]: The RMT DMA feature is not available on all ESP chips. Please check the data sheet before using it.

api

# API Reference

## Header files

- [include/led_strip.h](#file-includeled_striph)
- [include/led_strip_rmt.h](#file-includeled_strip_rmth)
- [include/led_strip_spi.h](#file-includeled_strip_spih)
- [include/led_strip_types.h](#file-includeled_strip_typesh)
- [interface/led_strip_interface.h](#file-interfaceled_strip_interfaceh)

## File include/led_strip.h

## Functions

| Type | Name |
| ---: | :--- |
|  esp\_err\_t | [**led\_strip\_clear**](#function-led_strip_clear) ([**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) strip) <br>_Clear LED strip (turn off all LEDs)_ |
|  esp\_err\_t | [**led\_strip\_del**](#function-led_strip_del) ([**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) strip) <br>_Free LED strip resources._ |
|  esp\_err\_t | [**led\_strip\_refresh**](#function-led_strip_refresh) ([**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) strip) <br>_Refresh memory colors to LEDs._ |
|  esp\_err\_t | [**led\_strip\_set\_pixel**](#function-led_strip_set_pixel) ([**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) strip, uint32\_t index, uint32\_t red, uint32\_t green, uint32\_t blue) <br>_Set RGB for a specific pixel._ |
|  esp\_err\_t | [**led\_strip\_set\_pixel\_hsv**](#function-led_strip_set_pixel_hsv) ([**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) strip, uint32\_t index, uint16\_t hue, uint8\_t saturation, uint8\_t value) <br>_Set HSV for a specific pixel._ |
|  esp\_err\_t | [**led\_strip\_set\_pixel\_rgbw**](#function-led_strip_set_pixel_rgbw) ([**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) strip, uint32\_t index, uint32\_t red, uint32\_t green, uint32\_t blue, uint32\_t white) <br>_Set RGBW for a specific pixel._ |

## Functions Documentation

### function `led_strip_clear`

_Clear LED strip (turn off all LEDs)_

```c
esp_err_t led_strip_clear (
    led_strip_handle_t strip
)
```

**Parameters:**

- `strip` LED strip

**Returns:**

- ESP\_OK: Clear LEDs successfully
- ESP\_FAIL: Clear LEDs failed because some other error occurred

### function `led_strip_del`

_Free LED strip resources._

```c
esp_err_t led_strip_del (
    led_strip_handle_t strip
)
```

**Parameters:**

- `strip` LED strip

**Returns:**

- ESP\_OK: Free resources successfully
- ESP\_FAIL: Free resources failed because error occurred

### function `led_strip_refresh`

_Refresh memory colors to LEDs._

```c
esp_err_t led_strip_refresh (
    led_strip_handle_t strip
)
```

**Parameters:**

- `strip` LED strip

**Returns:**

- ESP\_OK: Refresh successfully
- ESP\_FAIL: Refresh failed because some other error occurred

**Note:**

: After updating the LED colors in the memory, a following invocation of this API is needed to flush colors to strip.

### function `led_strip_set_pixel`

_Set RGB for a specific pixel._

```c
esp_err_t led_strip_set_pixel (
    led_strip_handle_t strip,
    uint32_t index,
    uint32_t red,
    uint32_t green,
    uint32_t blue
)
```

**Parameters:**

- `strip` LED strip
- `index` index of pixel to set
- `red` red part of color
- `green` green part of color
- `blue` blue part of color

**Returns:**

- ESP\_OK: Set RGB for a specific pixel successfully
- ESP\_ERR\_INVALID\_ARG: Set RGB for a specific pixel failed because of invalid parameters
- ESP\_FAIL: Set RGB for a specific pixel failed because other error occurred

### function `led_strip_set_pixel_hsv`

_Set HSV for a specific pixel._

```c
esp_err_t led_strip_set_pixel_hsv (
    led_strip_handle_t strip,
    uint32_t index,
    uint16_t hue,
    uint8_t saturation,
    uint8_t value
)
```

**Parameters:**

- `strip` LED strip
- `index` index of pixel to set
- `hue` hue part of color (0 - 360)
- `saturation` saturation part of color (0 - 255, rescaled from 0 - 1. e.g. saturation = 0.5, rescaled to 127)
- `value` value part of color (0 - 255, rescaled from 0 - 1. e.g. value = 0.5, rescaled to 127)

**Returns:**

- ESP\_OK: Set HSV color for a specific pixel successfully
- ESP\_ERR\_INVALID\_ARG: Set HSV color for a specific pixel failed because of an invalid argument
- ESP\_FAIL: Set HSV color for a specific pixel failed because other error occurred

### function `led_strip_set_pixel_rgbw`

_Set RGBW for a specific pixel._

```c
esp_err_t led_strip_set_pixel_rgbw (
    led_strip_handle_t strip,
    uint32_t index,
    uint32_t red,
    uint32_t green,
    uint32_t blue,
    uint32_t white
)
```

**Note:**

Only call this function if your led strip does have the white component (e.g. SK6812-RGBW)

**Note:**

Also see `led_strip_set_pixel` if you only want to specify the RGB part of the color and bypass the white component

**Parameters:**

- `strip` LED strip
- `index` index of pixel to set
- `red` red part of color
- `green` green part of color
- `blue` blue part of color
- `white` separate white component

**Returns:**

- ESP\_OK: Set RGBW color for a specific pixel successfully
- ESP\_ERR\_INVALID\_ARG: Set RGBW color for a specific pixel failed because of an invalid argument
- ESP\_FAIL: Set RGBW color for a specific pixel failed because other error occurred

## File include/led_strip_rmt.h

## Structures and Types

| Type | Name |
| ---: | :--- |
| struct | [**led\_strip\_rmt\_config\_t**](#struct-led_strip_rmt_config_t) <br>_LED Strip RMT specific configuration._ |
| struct | [**led\_strip\_rmt\_extra\_config**](#struct-led_strip_rmt_config_tled_strip_rmt_extra_config) <br> |

## Functions

| Type | Name |
| ---: | :--- |
|  esp\_err\_t | [**led\_strip\_new\_rmt\_device**](#function-led_strip_new_rmt_device) (const [**led\_strip\_config\_t**](#struct-led_strip_config_t) \*led\_config, const [**led\_strip\_rmt\_config\_t**](#struct-led_strip_rmt_config_t) \*rmt\_config, [**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) \*ret\_strip) <br>_Create LED strip based on RMT TX channel._ |

## Structures and Types Documentation

### struct `led_strip_rmt_config_t`

_LED Strip RMT specific configuration._

Variables:

- rmt\_clock\_source\_t clk_src  <br>RMT clock source

- struct [**led\_strip\_rmt\_config\_t::led\_strip\_rmt\_extra\_config**](#struct-led_strip_rmt_config_tled_strip_rmt_extra_config) flags  <br>Extra driver flags

- size\_t mem_block_symbols  <br>How many RMT symbols can one RMT channel hold at one time. Set to 0 will fallback to use the default size. Extra RMT specific driver flags

- uint32\_t resolution_hz  <br>RMT tick resolution, if set to zero, a default resolution (10MHz) will be applied

### struct `led_strip_rmt_config_t::led_strip_rmt_extra_config`

Variables:

- uint32\_t with_dma  <br>Use DMA to transmit data

## Functions Documentation

### function `led_strip_new_rmt_device`

_Create LED strip based on RMT TX channel._

```c
esp_err_t led_strip_new_rmt_device (
    const led_strip_config_t *led_config,
    const led_strip_rmt_config_t *rmt_config,
    led_strip_handle_t *ret_strip
)
```

**Parameters:**

- `led_config` LED strip configuration
- `rmt_config` RMT specific configuration
- `ret_strip` Returned LED strip handle

**Returns:**

- ESP\_OK: create LED strip handle successfully
- ESP\_ERR\_INVALID\_ARG: create LED strip handle failed because of invalid argument
- ESP\_ERR\_NO\_MEM: create LED strip handle failed because of out of memory
- ESP\_FAIL: create LED strip handle failed because some other error

## File include/led_strip_spi.h

## Structures and Types

| Type | Name |
| ---: | :--- |
| struct | [**led\_strip\_spi\_config\_t**](#struct-led_strip_spi_config_t) <br>_LED Strip SPI specific configuration._ |

## Functions

| Type | Name |
| ---: | :--- |
|  esp\_err\_t | [**led\_strip\_new\_spi\_device**](#function-led_strip_new_spi_device) (const [**led\_strip\_config\_t**](#struct-led_strip_config_t) \*led\_config, const [**led\_strip\_spi\_config\_t**](#struct-led_strip_spi_config_t) \*spi\_config, [**led\_strip\_handle\_t**](#typedef-led_strip_handle_t) \*ret\_strip) <br>_Create LED strip based on SPI MOSI channel._ |

## Structures and Types Documentation

### struct `led_strip_spi_config_t`

_LED Strip SPI specific configuration._

Variables:

- spi\_clock\_source\_t clk_src  <br>SPI clock source

- struct [**led\_strip\_spi\_config\_t**](#struct-led_strip_spi_config_t) flags  <br>Extra driver flags

- spi\_host\_device\_t spi_bus  <br>SPI bus ID. Which buses are available depends on the specific chip

- uint32\_t with_dma  <br>Use DMA to transmit data

## Functions Documentation

### function `led_strip_new_spi_device`

_Create LED strip based on SPI MOSI channel._

```c
esp_err_t led_strip_new_spi_device (
    const led_strip_config_t *led_config,
    const led_strip_spi_config_t *spi_config,
    led_strip_handle_t *ret_strip
)
```

**Note:**

Although only the MOSI line is used for generating the signal, the whole SPI bus can't be used for other purposes.

**Parameters:**

- `led_config` LED strip configuration
- `spi_config` SPI specific configuration
- `ret_strip` Returned LED strip handle

**Returns:**

- ESP\_OK: create LED strip handle successfully
- ESP\_ERR\_INVALID\_ARG: create LED strip handle failed because of invalid argument
- ESP\_ERR\_NOT\_SUPPORTED: create LED strip handle failed because of unsupported configuration
- ESP\_ERR\_NO\_MEM: create LED strip handle failed because of out of memory
- ESP\_FAIL: create LED strip handle failed because some other error

## File include/led_strip_types.h

## Structures and Types

| Type | Name |
| ---: | :--- |
| union  | [**led\_color\_component\_format\_t**](#union-led_color_component_format_t)  <br>_LED color component format._ |
| struct | [**format\_layout**](#struct-led_color_component_format_tformat_layout) <br> |
| enum  | [**led\_model\_t**](#enum-led_model_t)  <br>_LED strip model._ |
| struct | [**led\_strip\_config\_t**](#struct-led_strip_config_t) <br>_LED Strip common configurations The common configurations are not specific to any backend peripheral._ |
| struct | [**led\_strip\_extra\_flags**](#struct-led_strip_config_tled_strip_extra_flags) <br> |
| typedef struct [**led\_strip\_t**](#struct-led_strip_t) \* | [**led\_strip\_handle\_t**](#typedef-led_strip_handle_t)  <br>_Type of LED strip handle._ |

## Macros

| Type | Name |
| ---: | :--- |
| define  | [**LED\_STRIP\_COLOR\_COMPONENT\_FMT\_GRB**](#define-led_strip_color_component_fmt_grb)  ([**led\_color\_component\_format\_t**](#union-led_color_component_format_t)){.format = {.r\_pos = 1, .g\_pos = 0, .b\_pos = 2, .w\_pos = 3, .reserved = 0, .num\_components = 3}}<br>_Helper macros to set the color component format._ |
| define  | [**LED\_STRIP\_COLOR\_COMPONENT\_FMT\_GRBW**](#define-led_strip_color_component_fmt_grbw)  ([**led\_color\_component\_format\_t**](#union-led_color_component_format_t)){.format = {.r\_pos = 1, .g\_pos = 0, .b\_pos = 2, .w\_pos = 3, .reserved = 0, .num\_components = 4}}<br> |
| define  | [**LED\_STRIP\_COLOR\_COMPONENT\_FMT\_RGB**](#define-led_strip_color_component_fmt_rgb)  ([**led\_color\_component\_format\_t**](#union-led_color_component_format_t)){.format = {.r\_pos = 0, .g\_pos = 1, .b\_pos = 2, .w\_pos = 3, .reserved = 0, .num\_components = 3}}<br> |
| define  | [**LED\_STRIP\_COLOR\_COMPONENT\_FMT\_RGBW**](#define-led_strip_color_component_fmt_rgbw)  ([**led\_color\_component\_format\_t**](#union-led_color_component_format_t)){.format = {.r\_pos = 0, .g\_pos = 1, .b\_pos = 2, .w\_pos = 3, .reserved = 0, .num\_components = 4}}<br> |

## Structures and Types Documentation

### union `led_color_component_format_t`

_LED color component format._

**Note:**

The format is used to specify the order of color components in each pixel, also the number of color components.

Variables:

- struct [**led\_color\_component\_format\_t::format\_layout**](#struct-led_color_component_format_tformat_layout) format  <br>Format layout

- uint32\_t format_id  <br>Format ID

### struct `led_color_component_format_t::format_layout`

Variables:

- uint32\_t b_pos  <br>Position of the blue channel in the color order: 0~3

- uint32\_t g_pos  <br>Position of the green channel in the color order: 0~3

- uint32\_t num_components  <br>Number of color components per pixel: 3 or 4. If set to 0, it will fallback to 3

- uint32\_t r_pos  <br>Position of the red channel in the color order: 0~3

- uint32\_t reserved  <br>Reserved

- uint32\_t w_pos  <br>Position of the white channel in the color order: 0~3

### enum `led_model_t`

_LED strip model._

```c
enum led_model_t {
    LED_MODEL_WS2812,
    LED_MODEL_SK6812,
    LED_MODEL_INVALID
};
```

**Note:**

Different led model may have different timing parameters, so we need to distinguish them.

### struct `led_strip_config_t`

_LED Strip common configurations The common configurations are not specific to any backend peripheral._

Variables:

- [**led\_color\_component\_format\_t**](#union-led_color_component_format_t) color_component_format  <br>Specifies the order of color components in each pixel. Use helper macros like `LED_STRIP_COLOR_COMPONENT_FMT_GRB` to set the format LED strip extra driver flags

- struct [**led\_strip\_config\_t::led\_strip\_extra\_flags**](#struct-led_strip_config_tled_strip_extra_flags) flags  <br>Extra driver flags

- [**led\_model\_t**](#enum-led_model_t) led_model  <br>Specifies the LED strip model (e.g., WS2812, SK6812)

- uint32\_t max_leds  <br>Maximum number of LEDs that can be controlled in a single strip

- int strip_gpio_num  <br>GPIO number that used by LED strip

### struct `led_strip_config_t::led_strip_extra_flags`

Variables:

- uint32\_t invert_out  <br>Invert output signal

### typedef `led_strip_handle_t`

_Type of LED strip handle._

```c
typedef struct led_strip_t* led_strip_handle_t;
```

## Macros Documentation

### define `LED_STRIP_COLOR_COMPONENT_FMT_GRB`

_Helper macros to set the color component format._

```c
#define LED_STRIP_COLOR_COMPONENT_FMT_GRB ( led_color_component_format_t ){.format = {.r_pos = 1, .g_pos = 0, .b_pos = 2, .w_pos = 3, .reserved = 0, .num_components = 3}}
```

### define `LED_STRIP_COLOR_COMPONENT_FMT_GRBW`

```c
#define LED_STRIP_COLOR_COMPONENT_FMT_GRBW ( led_color_component_format_t ){.format = {.r_pos = 1, .g_pos = 0, .b_pos = 2, .w_pos = 3, .reserved = 0, .num_components = 4}}
```

### define `LED_STRIP_COLOR_COMPONENT_FMT_RGB`

```c
#define LED_STRIP_COLOR_COMPONENT_FMT_RGB ( led_color_component_format_t ){.format = {.r_pos = 0, .g_pos = 1, .b_pos = 2, .w_pos = 3, .reserved = 0, .num_components = 3}}
```

### define `LED_STRIP_COLOR_COMPONENT_FMT_RGBW`

```c
#define LED_STRIP_COLOR_COMPONENT_FMT_RGBW ( led_color_component_format_t ){.format = {.r_pos = 0, .g_pos = 1, .b_pos = 2, .w_pos = 3, .reserved = 0, .num_components = 4}}
```

## File interface/led_strip_interface.h

## Structures and Types

| Type | Name |
| ---: | :--- |
| struct | [**led\_strip\_t**](#struct-led_strip_t) <br>_LED strip interface definition._ |
| typedef struct led\_strip\_t | [**led\_strip\_t**](#typedef-led_strip_t)  <br> |

## Structures and Types Documentation

### struct `led_strip_t`

_LED strip interface definition._

Variables:

- esp\_err\_t(\* clear  <br>_Clear LED strip (turn off all LEDs)_<br>**Parameters:**

- `strip` LED strip
- `timeout_ms` timeout value for clearing task

**Returns:**

- ESP\_OK: Clear LEDs successfully
- ESP\_FAIL: Clear LEDs failed because some other error occurred

- esp\_err\_t(\* del  <br>_Free LED strip resources._<br>**Parameters:**

- `strip` LED strip

**Returns:**

- ESP\_OK: Free resources successfully
- ESP\_FAIL: Free resources failed because error occurred

- esp\_err\_t(\* refresh  <br>_Refresh memory colors to LEDs._<br>**Parameters:**

- `strip` LED strip
- `timeout_ms` timeout value for refreshing task

**Returns:**

- ESP\_OK: Refresh successfully
- ESP\_FAIL: Refresh failed because some other error occurred

**Note:**

: After updating the LED colors in the memory, a following invocation of this API is needed to flush colors to strip.

- esp\_err\_t(\* set_pixel  <br>_Set RGB for a specific pixel._<br>**Parameters:**

- `strip` LED strip
- `index` index of pixel to set
- `red` red part of color
- `green` green part of color
- `blue` blue part of color

**Returns:**

- ESP\_OK: Set RGB for a specific pixel successfully
- ESP\_ERR\_INVALID\_ARG: Set RGB for a specific pixel failed because of invalid parameters
- ESP\_FAIL: Set RGB for a specific pixel failed because other error occurred

- esp\_err\_t(\* set_pixel_rgbw  <br>_Set RGBW for a specific pixel. Similar to_ `set_pixel`_but also set the white component._<br>**Parameters:**

- `strip` LED strip
- `index` index of pixel to set
- `red` red part of color
- `green` green part of color
- `blue` blue part of color
- `white` separate white component

**Returns:**

- ESP\_OK: Set RGBW color for a specific pixel successfully
- ESP\_ERR\_INVALID\_ARG: Set RGBW color for a specific pixel failed because of an invalid argument
- ESP\_FAIL: Set RGBW color for a specific pixel failed because other error occurred

### typedef `led_strip_t`

```c
typedef struct led_strip_t led_strip_t;
```

Type of LED strip