led_strip_spi.h File Reference

#include <stdint.h>
#include "esp_err.h"
#include "driver/spi_master.h"
#include "led_strip_types.h"

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Data Structures
struct	led_strip_spi_config_t
	LED Strip SPI specific configuration. More...

Functions
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)
	Create LED strip based on SPI MOSI channel.

Function Documentation

led_strip_new_spi_device()

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 )

Create LED strip based on SPI MOSI channel.

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

Definition at line 123 of file led_strip_spi_dev.c.

{
    led_strip_spi_obj *spi_strip = NULL;
    esp_err_t ret = ESP_OK;
    ESP_GOTO_ON_FALSE(led_config && spi_config && ret_strip, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
    ESP_GOTO_ON_FALSE(led_config->led_pixel_format < LED_PIXEL_FORMAT_INVALID, ESP_ERR_INVALID_ARG, err, TAG, "invalid led_pixel_format");
    uint8_t bytes_per_pixel = 3;
    if (led_config->led_pixel_format == LED_PIXEL_FORMAT_GRBW) {
        bytes_per_pixel = 4;
    } else if (led_config->led_pixel_format == LED_PIXEL_FORMAT_GRB) {
        bytes_per_pixel = 3;
    } else {
        assert(false);
    }
    uint32_t mem_caps = MALLOC_CAP_DEFAULT;
    if (spi_config->flags.with_dma) {
        // DMA buffer must be placed in internal SRAM
        mem_caps |= MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA;
    }
    spi_strip = heap_caps_calloc(1, sizeof(led_strip_spi_obj) + led_config->max_leds * bytes_per_pixel * SPI_BYTES_PER_COLOR_BYTE, mem_caps);
 
    ESP_GOTO_ON_FALSE(spi_strip, ESP_ERR_NO_MEM, err, TAG, "no mem for spi strip");
 
    spi_strip->spi_host = spi_config->spi_bus;
    // for backward compatibility, if the user does not set the clk_src, use the default value
    spi_clock_source_t clk_src = SPI_CLK_SRC_DEFAULT;
    if (spi_config->clk_src) {
        clk_src = spi_config->clk_src;
    }
 
    spi_bus_config_t spi_bus_cfg = {
        .mosi_io_num = led_config->strip_gpio_num,
        //Only use MOSI to generate the signal, set -1 when other pins are not used.
        .miso_io_num = -1,
        .sclk_io_num = -1,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = led_config->max_leds * bytes_per_pixel * SPI_BYTES_PER_COLOR_BYTE,
    };
    ESP_GOTO_ON_ERROR(spi_bus_initialize(spi_strip->spi_host, &spi_bus_cfg, spi_config->flags.with_dma ? SPI_DMA_CH_AUTO : SPI_DMA_DISABLED), err, TAG, "create SPI bus failed");
 
    if (led_config->flags.invert_out == true) {
        esp_rom_gpio_connect_out_signal(led_config->strip_gpio_num, spi_periph_signal[spi_strip->spi_host].spid_out, true, false);
    }
 
    spi_device_interface_config_t spi_dev_cfg = {
        .clock_source = clk_src,
        .command_bits = 0,
        .address_bits = 0,
        .dummy_bits = 0,
        .clock_speed_hz = LED_STRIP_SPI_DEFAULT_RESOLUTION,
        .mode = 0,
        //set -1 when CS is not used
        .spics_io_num = -1,
        .queue_size = LED_STRIP_SPI_DEFAULT_TRANS_QUEUE_SIZE,
    };
 
    ESP_GOTO_ON_ERROR(spi_bus_add_device(spi_strip->spi_host, &spi_dev_cfg, &spi_strip->spi_device), err, TAG, "Failed to add spi device");
    //ensure the reset time is enough
    esp_rom_delay_us(10);
    int clock_resolution_khz = 0;
    spi_device_get_actual_freq(spi_strip->spi_device, &clock_resolution_khz);
    // TODO: ideally we should decide the SPI_BYTES_PER_COLOR_BYTE by the real clock resolution
    // But now, let's fixed the resolution, the downside is, we don't support a clock source whose frequency is not multiple of LED_STRIP_SPI_DEFAULT_RESOLUTION
    // clock_resolution between 2.2MHz to 2.8MHz is supported
    ESP_GOTO_ON_FALSE((clock_resolution_khz < LED_STRIP_SPI_DEFAULT_RESOLUTION / 1000 + 300) && (clock_resolution_khz > LED_STRIP_SPI_DEFAULT_RESOLUTION / 1000 - 300), ESP_ERR_NOT_SUPPORTED, err,
                      TAG, "unsupported clock resolution:%dKHz", clock_resolution_khz);
 
    spi_strip->bytes_per_pixel = bytes_per_pixel;
    spi_strip->strip_len = led_config->max_leds;
    spi_strip->base.set_pixel = led_strip_spi_set_pixel;
    spi_strip->base.set_pixel_rgbw = led_strip_spi_set_pixel_rgbw;
    spi_strip->base.refresh = led_strip_spi_refresh;
    spi_strip->base.clear = led_strip_spi_clear;
    spi_strip->base.del = led_strip_spi_del;
 
    *ret_strip = &spi_strip->base;
    return ESP_OK;
err:
    if (spi_strip) {
        if (spi_strip->spi_device) {
            spi_bus_remove_device(spi_strip->spi_device);
        }
        if (spi_strip->spi_host) {
            spi_bus_free(spi_strip->spi_host);
        }
        free(spi_strip);
    }
    return ret;
}

References led_strip_spi_obj::base, led_strip_spi_obj::bytes_per_pixel, led_strip_t::clear, led_strip_spi_config_t::clk_src, led_strip_t::del, ESP_GOTO_ON_ERROR, ESP_OK, led_strip_config_t::flags, led_strip_spi_config_t::flags, led_strip_config_t::invert_out, led_strip_config_t::led_pixel_format, LED_PIXEL_FORMAT_GRB, LED_PIXEL_FORMAT_GRBW, LED_PIXEL_FORMAT_INVALID, led_strip_spi_clear(), LED_STRIP_SPI_DEFAULT_RESOLUTION, LED_STRIP_SPI_DEFAULT_TRANS_QUEUE_SIZE, led_strip_spi_del(), led_strip_spi_refresh(), led_strip_spi_set_pixel(), led_strip_spi_set_pixel_rgbw(), led_strip_config_t::max_leds, led_strip_t::refresh, led_strip_t::set_pixel, led_strip_t::set_pixel_rgbw, led_strip_spi_config_t::spi_bus, SPI_BYTES_PER_COLOR_BYTE, led_strip_spi_obj::spi_device, led_strip_spi_obj::spi_host, led_strip_config_t::strip_gpio_num, led_strip_spi_obj::strip_len, TAG, and led_strip_spi_config_t::with_dma.

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