Parallel IO 模拟 SPI 或 I80 接口的 LCD

[English]

Parallel IO 并不是总线型的外设，驱动直接为 LCD 创建 Parallel IO 设备。目前驱动支持 SPI (1 bit 数据位宽) 和 I80 (8 bit 数据位宽 )模式。

  1. 调用 esp_lcd_new_panel_io_parl() 创建 Parallel IO 设备。请设置以下参数：

    esp_lcd_panel_io_handle_t io_handle = NULL;
esp_lcd_panel_io_parl_config_t io_config = {
    .clk_src = PARLIO_CLK_SRC_DEFAULT,
    .dc_gpio_num = EXAMPLE_PIN_NUM_DC,
    .clk_gpio_num = EXAMPLE_PIN_NUM_PCLK,
    .data_gpio_nums = {
        EXAMPLE_PIN_NUM_DATA0, // 驱动 SPI 接口的 LCD 时需要设置 DATA0，驱动 I80 接口的 LCD 时需要设置 DATA0~7
    },
    .data_width = 1, // 驱动 SPI 接口的 LCD 时数据宽度为 1，驱动 I80 接口的 LCD 时数据宽度为 8
    .max_transfer_bytes = EXAMPLE_LCD_H_RES * 100 * sizeof(uint16_t), // 单次最多可传输 100 行像素（假设像素格式为 RGB565）
    .dma_burst_size = EXAMPLE_DMA_BURST_SIZE,
    .cs_gpio_num = EXAMPLE_PIN_NUM_CS,
    .pclk_hz = EXAMPLE_LCD_PIXEL_CLOCK_HZ,
    .trans_queue_depth = 10,
    .dc_levels = {
        .dc_cmd_level = 0,
        .dc_data_level = 1,
    },
    .lcd_cmd_bits = EXAMPLE_LCD_CMD_BITS,
    .lcd_param_bits = EXAMPLE_LCD_PARAM_BITS,
};

ESP_ERROR_CHECK(esp_lcd_new_panel_io_parl(&io_config, io_handle));

  2. 安装 LCD 控制器驱动程序。LCD 控制器驱动程序负责向 LCD 控制器芯片发送命令和参数。在此步骤中，需要指定上一步骤中分配到的 Parallel IO 设备句柄以及一些面板特定配置：

    • esp_lcd_panel_dev_config_t::reset_gpio_num 设置 LCD 的硬件复位 GPIO 编号。如果 LCD 没有硬件复位管脚，则将此设置为 -1。

    • esp_lcd_panel_dev_config_t::rgb_ele_order 设置每个颜色数据的 RGB 元素顺序。

    • esp_lcd_panel_dev_config_t::bits_per_pixel 设置像素颜色数据的位宽。LCD 驱动程序使用此值计算要发送到 LCD 控制器芯片的字节数。

    • esp_lcd_panel_dev_config_t::data_endian 指定传输到屏幕的数据的字节序。不超过一字节的颜色格式（如 RGB232）不需要指定数据字节序。若驱动程序不支持指定数据字节序，则将忽略此字段。

    esp_lcd_panel_handle_t panel_handle = NULL;
esp_lcd_panel_dev_config_t panel_config = {
    .reset_gpio_num = EXAMPLE_PIN_NUM_RST,
    .rgb_ele_order = LCD_RGB_ELEMENT_ORDER_BGR,
    .bits_per_pixel = 16,
};
// 为 ST7789 创建 LCD 面板句柄，并指定 Parallel IO 设备句柄
ESP_ERROR_CHECK(esp_lcd_new_panel_st7789(io_handle, &panel_config, &panel_handle));

API 参考

Header File

  • components/esp_lcd/include/esp_lcd_io_parl.h

  • This header file can be included with:

    #include "esp_lcd_io_parl.h"

  • This header file is a part of the API provided by the esp_lcd component. To declare that your component depends on esp_lcd, add the following to your CMakeLists.txt:

    REQUIRES esp_lcd

    or

    PRIV_REQUIRES esp_lcd

Functions

esp_err_t esp_lcd_new_panel_io_parl(const esp_lcd_panel_io_parl_config_t *io_config, esp_lcd_panel_io_handle_t *ret_io)

Create LCD panel IO, for parlio interface.

参数

  • io_config -- [in] IO configuration, for parlio interface

  • ret_io -- [out] Returned panel IO handle

返回

  • ESP_ERR_INVALID_ARG if parameter is invalid

  • ESP_ERR_NOT_SUPPORTED if some configuration can't be satisfied, e.g. pixel clock out of the range

  • ESP_ERR_NO_MEM if out of memory

  • ESP_OK on success

void *esp_lcd_parlio_alloc_draw_buffer(esp_lcd_panel_io_handle_t io, size_t size, uint32_t caps)

Allocate a draw buffer that can be used by parlio interface LCD panel.

备注

This function differs from the normal 'heap_caps_*' functions in that it can also automatically handle the alignment required by DMA burst, cache line size, etc.

参数

  • io -- [in] Panel IO handle, created by esp_lcd_new_panel_io_parl()

  • size -- [in] Size of memory to be allocated

  • caps -- [in] Bitwise OR of MALLOC_CAP_* flags indicating the type of memory desired for the allocation

返回

Pointer to a new buffer of size 'size' with capabilities 'caps', or NULL if allocation failed

Structures

struct esp_lcd_panel_io_parl_config_t

Parallel Panel IO configuration structure, for intel 8080 interface(8 data-lines) or SPI interface(1 data-lines)

Public Members

int dc_gpio_num

GPIO used for D/C line

int clk_gpio_num

GPIO used for CLK line

int cs_gpio_num

GPIO used for CS line

int data_gpio_nums[ESP_PARLIO_LCD_WIDTH_MAX]

GPIOs used for data lines

size_t data_width

Number of data lines, 1(SPI) or 8(I80)

uint32_t pclk_hz

Frequency of pixel clock

parlio_clock_source_t clk_src

Clock source for the Parlio peripheral

size_t max_transfer_bytes

Maximum transfer size, this determines the length of internal DMA link

size_t dma_burst_size

DMA burst size, in bytes

size_t trans_queue_depth

Transaction queue size, larger queue, higher throughput

int lcd_cmd_bits

Bit-width of LCD command

int lcd_param_bits

Bit-width of LCD parameter

unsigned int dc_cmd_level

Level of DC line in CMD phase

unsigned int dc_data_level

Level of DC line in DATA phase

struct esp_lcd_panel_io_parl_config_t::[anonymous] dc_levels

Each LCD device might have its own D/C control logic

unsigned int cs_active_high

If set, a high level of CS line will select the device, otherwise, CS line is low level active

struct esp_lcd_panel_io_parl_config_t::[anonymous] flags

Panel IO config flags

Macros

ESP_PARLIO_LCD_WIDTH_MAX

Maximum data width of parlio lcd interface

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