RT-Thread开发之路（8）— 通过TFTLCD液晶屏幕显示数据

RT-Thread开发之路（8）— 通过TFTLCD液晶屏幕显示数据

一、硬件连接

BearPi上和正点原子的潘多拉开发板上一样，安装了一个1.3寸，分辨率240*240，色彩深度16bit 的SPI通信接口的TFTLCD液晶彩屏，其驱动芯片为ST7789V2，且连接方式都一样采用4线SPI，如下所示，左边是BearPi，右边是atk-pandora的连接图。

二、开启SPI设备

打开board.h文件，找到SPI的配置处，按照其提示配置：

首先，打开【RT-Thread Settings】，找到SPI设备驱动程序，将其选中，然后保存使之生效

通过查看原理图，可以知道，其连接到的引脚如下所示：

LCD引脚	MCU引脚
SPI2_MPSI	PC3
SPI2_SCK	PB13
LCD_WR_RS	PC6
LCD_EESET	PC7
LCD_POWER	PB15

将board.h的SPI2的注释打开，

接下来使用CubeMx生成HAL_SPI_MspInit()函数，将SPI以及LCD需要的控制引脚设置为如图所示：

将HAL_SPI_MspInit()复制到board.c里

void HAL_SPI_MspInit(SPI_HandleTypeDef* spiHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(spiHandle->Instance==SPI2)
  {
  /* USER CODE BEGIN SPI2_MspInit 0 */

  /* USER CODE END SPI2_MspInit 0 */
    /* SPI2 clock enable */
    __HAL_RCC_SPI2_CLK_ENABLE();
  
    __HAL_RCC_GPIOC_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**SPI2 GPIO Configuration    
    PC3     ------> SPI2_MOSI
    PB13     ------> SPI2_SCK 
    */
    GPIO_InitStruct.Pin = GPIO_PIN_3;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = GPIO_PIN_13;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /* USER CODE BEGIN SPI2_MspInit 1 */

  /* USER CODE END SPI2_MspInit 1 */
  }
}

然后打开stm32xxxx_hal_config.h文件，将#define HAL_SPI_MODULE_ENABLED的注释去掉：

然后编译下载运行，在msh下输入list_device，可以看到，spi2已经注册上去了

三、移植LCD代码

在packages文件夹下新建lcd_st7789v2文件夹，并将并将潘多拉开发板IoT_Board的drv_lcd.c、drv_lcd.h、drv_lcd_font.h三个文件放入其中，获取方式为：从 Github 获取 或 从 Gitee 获取。

然后我们需要对drv_lcd.c做一些修改，首先，去掉gpio.h头文件：

然后修改LCD_PWR_PIN，LCD_DC_PIN，LCD_RES_PIN引脚定义：

#define LCD_PWR_PIN           GET_PIN(B, 15)
#define LCD_DC_PIN            GET_PIN(C, 6)
#define LCD_RES_PIN           GET_PIN(C, 7)

接下来，在rt_hw_lcd_config()函数修改两行代码，添加一行代码：

spi_dev_lcd = (struct rt_spi_device *)rt_device_find("spi20"); //修改
cfg.mode = RT_SPI_MASTER | RT_SPI_MODE_2 | RT_SPI_MSB;			//修改
spi_dev_lcd->bus->owner = spi_dev_lcd;							//添加

然后，我们对rt_hw_lcd_init()需要做比较大的修改，就直接贴上修改完成的代码：

static int rt_hw_lcd_init(void)
{
    rt_hw_spi_device_attach("spi2", "spi20", GPIOC, GPIO_PIN_13);
    lcd_gpio_init();
    rt_thread_mdelay(50);

    rt_pin_write(LCD_PWR_PIN, PIN_LOW);
    rt_pin_write(LCD_RES_PIN, PIN_LOW);
    rt_thread_mdelay(12);
    rt_pin_write(LCD_RES_PIN, PIN_HIGH);
    rt_pin_write(LCD_PWR_PIN, PIN_LOW);
    rt_pin_write(LCD_RES_PIN, PIN_LOW);
    rt_thread_mdelay(12);
    rt_pin_write(LCD_RES_PIN, PIN_HIGH);
    rt_thread_mdelay(12);
    /* Sleep Out */
    lcd_write_cmd(0x11);
    /* wait for power stability */
    rt_thread_mdelay(12);

    /* Memory Data Access Control */
    lcd_write_cmd(0x36);
    lcd_write_data(0x00);
    /* RGB 5-6-5-bit  */
    lcd_write_cmd(0x3A);
    lcd_write_data(0x65);
    /* Porch Setting */
    lcd_write_cmd(0xB2);
    lcd_write_data(0x0C);
    lcd_write_data(0x0C);
    lcd_write_data(0x00);
    lcd_write_data(0x33);
    lcd_write_data(0x33);
    /*  Gate Control */
    lcd_write_cmd(0xB7);
    lcd_write_data(0x72);
    /* VCOM Setting */
    lcd_write_cmd(0xBB);
    lcd_write_data(0x3D);
    /* LCM Control */
    lcd_write_cmd(0xC0);
    lcd_write_data(0x2C);
    /* VDV and VRH Command Enable */
    lcd_write_cmd(0xC2);
    lcd_write_data(0x01);
    /* VRH Set */
    lcd_write_cmd(0xC3);
    lcd_write_data(0x19);
    /* VDV Set */
    lcd_write_cmd(0xC4);
    lcd_write_data(0x20);
    /* Frame Rate Control in Normal Mode */
    lcd_write_cmd(0xC6);
    lcd_write_data(0x0F);
    /* Power Control 1 */
    lcd_write_cmd(0xD0);
    lcd_write_data(0xA4);
    lcd_write_data(0xA1);
    /* Positive Voltage Gamma Control */
    lcd_write_cmd(0xE0);
    lcd_write_data(0xD0);
    lcd_write_data(0x04);
    lcd_write_data(0x0D);
    lcd_write_data(0x11);
    lcd_write_data(0x13);
    lcd_write_data(0x2B);
    lcd_write_data(0x3F);
    lcd_write_data(0x54);
    lcd_write_data(0x4C);
    lcd_write_data(0x18);
    lcd_write_data(0x0D);
    lcd_write_data(0x0B);
    lcd_write_data(0x1F);
    lcd_write_data(0x23);
    /* Negative Voltage Gamma Control */
    lcd_write_cmd(0xE1);
    lcd_write_data(0xD0);
    lcd_write_data(0x04);
    lcd_write_data(0x0C);
    lcd_write_data(0x11);
    lcd_write_data(0x13);
    lcd_write_data(0x2C);
    lcd_write_data(0x3F);
    lcd_write_data(0x44);
    lcd_write_data(0x51);
    lcd_write_data(0x2F);
    lcd_write_data(0x1F);
    lcd_write_data(0x1F);
    lcd_write_data(0x20);
    lcd_write_data(0x23);
    /* Display Inversion On */
    lcd_write_cmd(0x21);

    lcd_write_cmd(0x29);

    lcd_address_set(0, 0, 240 - 1, 240 - 1);

    lcd_clear(WHITE);

    /* display on */
    rt_pin_write(LCD_PWR_PIN, PIN_HIGH);

    return RT_EOK;
}
INIT_COMPONENT_EXPORT(rt_hw_lcd_init);

接下来添加头文件，在工具设置配置页，点击GNU ARM Cross C Compiler下的Includes配置项即可打开头文件路径配置参数，点击Inlucde paths（-I）配置栏的添加按钮即将’lcd_st7789v2`目录添加进来，如下图所示：

四、编写代码，在LCD上显示

在main.c里添加头文件，

#include "drv_lcd.h"

然后测试几个函数：

    /* 设置背景色和前景色 */
    lcd_set_color(WHITE, BLACK);

    /* 在 LCD 上显示字符 */
    lcd_show_string(10, 60, 32, "Hello!");
    lcd_show_string(10, 100, 32, "RT-Thread");

    /* 在 LCD 上画线 */
    lcd_draw_line(0, 69+16+24+32, 240, 69+16+24+32);

    /* 在 LCD 上画一个同心圆 */
    lcd_draw_point(120, 194);
    for (int i = 0; i < 46; i += 4)
    {
        lcd_draw_circle(120, 194, i);
    }

编译下载运行，可以看到：