一、概述
- 开发板：STM32F103C8T6
- 显示器：ST7735S
- RT-Thread：5.0.0
玩过 GUI 的小伙伴都知道，界面的显示是一个个像素点组合起来的，那么直接构建出来炫酷的 GUI 还是相对比较困难的，所以我们一般都会使用一些 GUI 库来实现，比如 LVGL、QT、UGUI等，这样对于驱动开发的人员来说就相对比较简单了，
图形库应用的核心思想只需要提供一帧的缓冲区，我们只需要不断的将缓冲区的数据写入到 LCD 中即可，而缓冲区的内容由图形库实现，需要注意的是这个缓冲的创建方式，有的图形库会自己创建缓冲区，我们只需要负责刷新 LCD 的显示即可，而有的图形库是由驱动提供缓冲区，图形库负责写入。
二、RT-Thread 移植
移植 RT-Thread 不是此文章的重点，可以参考一下我之前的笔记，或者直接使用 RT-Thread Studio、STM32CubeMX等工具直接生成，这里我就不过多介绍了
三、LCD 驱动
使用过 RT-Thread 的小伙伴，都知道 RT-Thread 目前还不能直接使用工具生成我们想要的 LCD 驱动，所以这里我们只能根据标准的驱动进行编写了
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驱动函数结构体
/* 驱动函数实现的结构体 */ #ifdef RT_USING_DEVICE_OPS const static struct rt_device_ops lcd_ops = { drv_lcd_init, RT_NULL, RT_NULL, RT_NULL, RT_NULL, drv_lcd_control }; #endif -
注册 LCD 设备
int drv_lcd_hw_init(void) { rt_err_t result = RT_EOK; rt_uint32_t lcd_buff_size = lcd_buff_size = LCD_HEIGHT * LCD_WIDTH * 2; /* 创建LCD设备对象 */ struct rt_device *device = &_lcd.lcd_dev; memset(&_lcd, 0x00, sizeof(_lcd)); LOG_D("drv_lcd_hw_init!n"); /* 初始化lcd_lock信号量 */ result = rt_sem_init(&_lcd.lcd_lock, "lcd_lock", 0, RT_IPC_FLAG_FIFO); if (result != RT_EOK) { LOG_E("init semaphore failed!n"); result = -RT_ENOMEM; goto __exit; } /* 设置 LCD 设备信息 */ _lcd.lcd_info.height = LCD_HEIGHT; _lcd.lcd_info.width = LCD_WIDTH; _lcd.lcd_info.bits_per_pixel = LCD_BITS_PER_PIXEL; _lcd.lcd_info.pixel_format = RTGRAPHIC_PIXEL_FORMAT_RGB565; // 图像的格式（RGB：565） /* LCD 显示缓冲区，大小为显示一帧图像所需空间 */ _lcd.lcd_info.smem_len = lcd_buff_size; _lcd.lcd_info.framebuffer = rt_malloc(lcd_buff_size); if (_lcd.lcd_info.framebuffer == RT_NULL) { LOG_E("init frame buffer failed!n"); result = -RT_ENOMEM; goto __exit; } /* 将缓冲区初始化为 0xFF */ memset(_lcd.lcd_info.framebuffer, 0xFF, lcd_buff_size); #ifdef RT_USING_DEVICE_OPS device->ops = &lcd_ops; #else device->init = drv_lcd_init; device->control = drv_lcd_control; #endif /* 注册 LCD 设备 */ rt_device_register(device, "lcd", RT_DEVICE_FLAG_RDWR); __exit: if (result != RT_EOK) { rt_sem_detach(&_lcd.lcd_lock); if (_lcd.lcd_info.framebuffer) { rt_free(_lcd.lcd_info.framebuffer); } } return result; } -
LCD 控制函数的实现
static rt_err_t drv_lcd_control(struct rt_device *device, int cmd, void *args) { // struct drv_lcd_device *lcd = LCD_DEVICE(device); LOG_D("drv_lcd_control cmd is: %dn", cmd); switch (cmd) { case RTGRAPHIC_CTRL_RECT_UPDATE: { rt_sem_take(&_lcd.lcd_lock, RT_TICK_PER_SECOND / 20); /* 刷新缓冲区 */ rt_sem_release(&_lcd.lcd_lock); } break; case RTGRAPHIC_CTRL_POWERON: { /* LCD 退出睡眠模式 */ } break; case RTGRAPHIC_CTRL_POWEROFF: { /* LCD 进入睡眠模式 */ } break; case RTGRAPHIC_CTRL_GET_INFO: { /* 获取 LCD 参数 */ memcpy(args, &_lcd.lcd_info, sizeof(_lcd.lcd_info)); } break; default: return -RT_EINVAL; } return RT_EOK; } -
LCD 驱动功能实现
剩下的就比较简单了，只需要参考 LCD 提供的案例程序进行更改就好了，主要有实现如下- drv_lcd_init： 完成 LCD 的复位、初始化、首次清屏工作
- drv_lcd_control： 完成 LCD 显示区域的刷新、屏幕参数的返回、亮屏和息屏等工作
注意：具体实现参考后面的程序源码，相对比较简单，这里就不过多介绍了
四、UGUI 介绍
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介绍
µGUI 是一个用于嵌入式系统的免费开源图形库。 它独立于平台，可以轻松移植到几乎任何微控制器系统。 只要显示器能够显示图形，μGUI 就不受某种显示技术的限制。 因此，支持LCD、TFT、E-Paper、LED或OLED等显示技术。 整个模块由两个文件组成：ugui.c 和 ugui.h。
注意：这里的介绍我直接引用了作者的描述 -
获取 UGUI
github：https://github.com/xidongxu/ugui -
文件目录
-
使用介绍
- 移植： 我们主要实现 ugui_port.c，这里下载时已经提供了案例，所以我只需要在其中进行简单的修改
- 使用： 使用相对比较简单，直接参考 “µGUI v0.3.pdf” 文档即可，直接没有难度
五、UGUI 移植
-
初始化
直接在 ugui_port.c 文件中使用INIT_COMPONENT_EXPORT(ugui_port_init)进行自动初始化，如下图所示：
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lcd_open 函数
这里不要做任何更改，从函数中可以看出 LCD 相关的参数获取，如下图所示：
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lcd_draw_pixel 函数
主要功能是在缓冲区中写入一个像素点的颜色，如下图所示：
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ugui_port_thread_entry 函数
这是线程的入口函数，主要目的是定期将缓冲区的数据写入到 LCD 中，下图所示：
注意：从以上步奏可以看出，移植 UGUI 时不需要更改任何参数，只需要在初始化时调用 ugui_port_init 函数即可。
六、程序源码
drv_lcd_st7735s.h
/** * @file drv_lcd_st7735s.h * */ #ifndef __DRV_LCD_ST7735S_H__ #define __DRV_LCD_ST7735S_H__ #include <rtthread.h> #define LCD_HEIGHT 20 // LCD 高像素 #define LCD_WIDTH 128 // LCD 宽像素 #define LCD_BITS_PER_PIXEL 16 // 像素点的数据宽度 #define LCD_CS_PIN_TYPE GPIOA // CS 引脚所在的组 #define LCD_CS_PIN GPIO_PIN_4 // 引脚编号 #define LCD_BCK_PIN GET_PIN(B, 1) // 背光引脚 #define LCD_DC_PIN GET_PIN(B, 8) // 数据引脚 #define LCD_RES_PIN GET_PIN(B, 9) // 复位引脚 #define WHITE 0xFFFF #define BLACK 0x0000 #define BLUE 0x001F #define BRED 0XF81F #define GRED 0XFFE0 #define GBLUE 0X07FF #define RED 0xF800 #define MAGENTA 0xF81F #define GREEN 0x07E0 #define CYAN 0x7FFF #define YELLOW 0xFFE0 #define BROWN 0XBC40 #define BRRED 0XFC07 #define GRAY 0X8430 #define GRAY175 0XAD75 #define GRAY151 0X94B2 #define GRAY187 0XBDD7 #define GRAY240 0XF79E #endif /* __DRV_LCD_ST7735S_H__ */ drv_lcd_st7735s.c
/*************************************************************** 文件名 : drv_lcd_st7735s.c 作者 : jiaozhu 版本 : V1.0 描述 : st7735s 显示驱动 其他 : 无 日志 : 初版 V1.0 2023/04/28 ***************************************************************/ #include <board.h> #include <rtthread.h> #ifdef BSP_USING_LCD #include "drv_spi.h" #include <string.h> #include "drv_lcd_st7735s.h" //#define DRV_DEBUG #define LOG_TAG "drv.lcd" #include <drv_log.h> static struct rt_spi_device *spi_dev_lcd; struct drv_lcd_device { struct rt_device lcd_dev; struct rt_device_graphic_info lcd_info; struct rt_semaphore lcd_lock; }; struct drv_lcd_device _lcd; /** * @brief LCD 命令写入，写入时数据引脚为低电平 * * @param cmd 命令 * @retval 返回执行结果 */ static rt_err_t lcd_write_cmd(const rt_uint8_t cmd) { rt_size_t len; rt_pin_write(LCD_DC_PIN, PIN_LOW); len = rt_spi_send(spi_dev_lcd, &cmd, 1); if (len != 1) { LOG_I("lcd_write_cmd error. %d", len); return -RT_ERROR; } else { return RT_EOK; } } /** * @brief LCD 数据写入，写入时数据引脚为高电平 * * @param cmd 命令 * @retval 返回执行结果 */ static rt_err_t lcd_write_data(const rt_uint8_t data) { rt_size_t len; rt_pin_write(LCD_DC_PIN, PIN_HIGH); len = rt_spi_send(spi_dev_lcd, &data, 1); if (len != 1) { LOG_I("lcd_write_data error. %d", len); return -RT_ERROR; } else { return RT_EOK; } } /** * @brief LCD 板级初始化 * * @param None * @retval int 初始化结果 */ static int lcd_dev_init(void) { lcd_write_cmd(0x11); //Sleep out rt_thread_delay(12); //Delay 12ms //------------------------------------ST7735S Frame Rate-----------------------------------------// lcd_write_cmd(0xB1); lcd_write_data(0x05); lcd_write_data(0x3C); lcd_write_data(0x3C); lcd_write_cmd(0xB2); lcd_write_data(0x05); lcd_write_data(0x3C); lcd_write_data(0x3C); lcd_write_cmd(0xB3); lcd_write_data(0x05); lcd_write_data(0x3C); lcd_write_data(0x3C); lcd_write_data(0x05); lcd_write_data(0x3C); lcd_write_data(0x3C); //------------------------------------End ST7735S Frame Rate-----------------------------------------// lcd_write_cmd(0xB4); //Dot inversion lcd_write_data(0x03); lcd_write_cmd(0xC0); lcd_write_data(0x28); lcd_write_data(0x08); lcd_write_data(0x04); lcd_write_cmd(0xC1); lcd_write_data(0XC0); lcd_write_cmd(0xC2); lcd_write_data(0x0D); lcd_write_data(0x00); lcd_write_cmd(0xC3); lcd_write_data(0x8D); lcd_write_data(0x2A); lcd_write_cmd(0xC4); lcd_write_data(0x8D); lcd_write_data(0xEE); //---------------------------------End ST7735S Power Sequence-------------------------------------// lcd_write_cmd(0xC5); //VCOM lcd_write_data(0x1A); lcd_write_cmd(0x36); //MX, MY, RGB mode lcd_write_data(0xC0); //------------------------------------ST7735S Gamma Sequence-----------------------------------------// lcd_write_cmd(0xE0); lcd_write_data(0x04); lcd_write_data(0x22); lcd_write_data(0x07); lcd_write_data(0x0A); lcd_write_data(0x2E); lcd_write_data(0x30); lcd_write_data(0x25); lcd_write_data(0x2A); lcd_write_data(0x28); lcd_write_data(0x26); lcd_write_data(0x2E); lcd_write_data(0x3A); lcd_write_data(0x00); lcd_write_data(0x01); lcd_write_data(0x03); lcd_write_data(0x13); lcd_write_cmd(0xE1); lcd_write_data(0x04); lcd_write_data(0x16); lcd_write_data(0x06); lcd_write_data(0x0D); lcd_write_data(0x2D); lcd_write_data(0x26); lcd_write_data(0x23); lcd_write_data(0x27); lcd_write_data(0x27); lcd_write_data(0x25); lcd_write_data(0x2D); lcd_write_data(0x3B); lcd_write_data(0x00); lcd_write_data(0x01); lcd_write_data(0x04); lcd_write_data(0x13); //------------------------------------End ST7735S Gamma Sequence-----------------------------------------// lcd_write_cmd(0x3A); //65k mode lcd_write_data(0x05); lcd_write_cmd(0x29); //Display on return RT_EOK; } /** * @brief 初始化 LCD 所需的引脚，并通过引脚复位 LCD * * @param None * @retval None */ static void lcd_gpio_init(void) { /* 配置引脚模式 */ rt_pin_mode(LCD_DC_PIN, PIN_MODE_OUTPUT); rt_pin_mode(LCD_RES_PIN, PIN_MODE_OUTPUT); rt_pin_mode(LCD_BCK_PIN, PIN_MODE_OUTPUT); /* 通过引脚复位 LCD */ rt_pin_write(LCD_BCK_PIN, PIN_LOW); rt_pin_write(LCD_RES_PIN, PIN_LOW); rt_thread_mdelay(12); rt_pin_write(LCD_RES_PIN, PIN_HIGH); /* 复位后延时一段时间，确保屏幕正常工作 */ rt_thread_mdelay(12); } /** * @brief 初始化 LCD 所需的 SPI 外设 * * @param None * @retval int 操作结果 */ static int lcd_spi_init(void) { /* 配置 SPI 端口，并指定 CS 引脚为 PA4 */ __HAL_RCC_GPIOA_CLK_ENABLE(); rt_hw_spi_device_attach("spi1", "spi10", LCD_CS_PIN_TYPE, LCD_CS_PIN); /* 查找设备 */ spi_dev_lcd = (struct rt_spi_device *)rt_device_find("spi10"); if(RT_NULL == spi_dev_lcd) { LOG_E("Unable to find SPI device required for LCD"); return RT_ERROR; } /* 配置 SPI */ struct rt_spi_configuration cfg; cfg.data_width = 8; cfg.mode = RT_SPI_MASTER | RT_SPI_MODE_0 | RT_SPI_MSB; cfg.max_hz = 42 * 1000 * 1000; /* 42M,SPI max 42MHz,lcd 4-wire spi */ spi_dev_lcd->bus ->owner = spi_dev_lcd; rt_spi_configure(spi_dev_lcd, &cfg); return RT_EOK; } /** * @brief 设置需要绘图的区域 * * @param x1 start of x position * @param y1 start of y position * @param x2 end of x position * @param y2 end of y position * @retval None */ static void lcd_draw_area_set(rt_uint16_t x1, rt_uint16_t y1, rt_uint16_t x2, rt_uint16_t y2) { lcd_write_cmd(0x2a); lcd_write_data(x1 >> 8); lcd_write_data(x1); lcd_write_data(x2 >> 8); lcd_write_data(x2); lcd_write_cmd(0x2b); lcd_write_data(y1 >> 8); lcd_write_data(y1); lcd_write_data(y2 >> 8); lcd_write_data(y2); lcd_write_cmd(0x2C); } /** * @brief LCD 清屏，将整个屏幕设定为指定颜色 * * @param color 清空的颜色 * @retval None */ static void lcd_clear_screen(rt_uint16_t color) { rt_uint16_t i, j; rt_uint8_t data[2] = {0}; data[0] = (color >> 8) & 0xFF; data[1] = color & 0xFF; /* 设置整个屏幕区域 */ lcd_draw_area_set(0, 0, LCD_WIDTH - 1, LCD_HEIGHT - 1); /* 这里直接通过 SPI 发送数据，所以需要单独将数据引脚拉高 */ rt_pin_write(LCD_DC_PIN, PIN_HIGH); if (_lcd.lcd_info.framebuffer != RT_NULL) { /* 重置缓冲区 */ // memset(_lcd.lcd_info.framebuffer, color, _lcd.lcd_info.smem_len); for (j = 0; j < _lcd.lcd_info.smem_len / 2; j++) { _lcd.lcd_info.framebuffer[j * 2] = data[0] ; _lcd.lcd_info.framebuffer[j * 2 + 1] = data[1]; } rt_spi_send(spi_dev_lcd, _lcd.lcd_info.framebuffer, _lcd.lcd_info.smem_len); } else { for (i = 0; i < LCD_HEIGHT; i++) { for (j = 0; j < LCD_WIDTH; j++) { rt_spi_send(spi_dev_lcd, data, 2); } } } } /** * @brief 点亮 LED 屏幕 * @param None * @retval None */ static void lcd_display_on(void) { rt_pin_write(LCD_BCK_PIN, PIN_HIGH); } /** * @brief 熄灭 LED 屏幕 * @param None * @retval None */ static void lcd_display_off(void) { rt_pin_write(LCD_BCK_PIN, PIN_LOW); } /** * @brief 液晶显示器进入最小功耗模式，背光关闭 * @param None * @retval None */ static void lcd_enter_sleep(void) { rt_pin_write(LCD_BCK_PIN, PIN_LOW); rt_thread_mdelay(5); lcd_write_cmd(0x10); } /** * @brief 液晶显示器关闭睡眠模式，背光灯打开 * @param None * @retval None */ static void lcd_exit_sleep(void) { rt_pin_write(LCD_BCK_PIN, PIN_HIGH); rt_thread_mdelay(5); lcd_write_cmd(0x11); rt_thread_mdelay(120); } /** * @brief 设置光标位置 * @param Xpos 横坐标 * @param Ypos 纵坐标 * @retval None */ // static void lcd_cursor_set(rt_uint16_t Xpos, rt_uint16_t Ypos) // { // lcd_write_cmd(0x2A); // lcd_write_data(Xpos>>8); // lcd_write_data(Xpos&0XFF); // lcd_write_cmd(0x2B); // lcd_write_data(Ypos>>8); // lcd_write_data(Ypos&0XFF); // } /** * @brief LCD 驱动初始化 * @param device LCD 设备结构体 * @retval None */ static rt_err_t drv_lcd_init(struct rt_device *device) { LOG_D("drv_lcd_init!n"); if (lcd_spi_init() != RT_EOK) { return -RT_EINVAL; } lcd_gpio_init(); if (lcd_dev_init() != RT_EOK) { return -RT_EINVAL; } /* 清屏 */ lcd_clear_screen(WHITE); /* 初始化完成后，点亮屏幕 */ rt_pin_write(LCD_BCK_PIN, PIN_HIGH); return RT_EOK; } /** * @brief LCD 驱动的操作函数 * @param device LCD 设备结构体 * @param cmd 操作命令 * @param args 传入的参数 * @retval None */ static rt_err_t drv_lcd_control(struct rt_device *device, int cmd, void *args) { // struct drv_lcd_device *lcd = LCD_DEVICE(device); LOG_D("drv_lcd_control cmd is: %dn", cmd); switch (cmd) { case RTGRAPHIC_CTRL_RECT_UPDATE: { rt_sem_take(&_lcd.lcd_lock, RT_TICK_PER_SECOND / 20); /* 刷新缓冲区 */ if (_lcd.lcd_info.framebuffer) { /* 设置整个屏幕区域 */ lcd_draw_area_set(0, 0, LCD_WIDTH - 1, LCD_HEIGHT - 1); /* 这里直接通过 SPI 发送数据，所以需要单独将数据引脚拉高 */ rt_pin_write(LCD_DC_PIN, PIN_HIGH); rt_spi_send(spi_dev_lcd, _lcd.lcd_info.framebuffer, _lcd.lcd_info.smem_len); } /* 释放锁信号 */ rt_sem_release(&_lcd.lcd_lock); } break; case RTGRAPHIC_CTRL_POWERON: { /* LCD 退出睡眠模式 */ lcd_display_on(); lcd_exit_sleep(); } break; case RTGRAPHIC_CTRL_POWEROFF: { /* LCD 进入睡眠模式 */ lcd_display_off(); lcd_enter_sleep(); } break; case RTGRAPHIC_CTRL_GET_INFO: { /* 获取 LCD 参数 */ memcpy(args, &_lcd.lcd_info, sizeof(_lcd.lcd_info)); } break; default: return -RT_EINVAL; } return RT_EOK; } /* 驱动函数实现的结构体 */ #ifdef RT_USING_DEVICE_OPS const static struct rt_device_ops lcd_ops = { drv_lcd_init, RT_NULL, RT_NULL, RT_NULL, RT_NULL, drv_lcd_control }; #endif /** * @brief LCD 设备注册 * * @param None * @retval int 注册结果 */ int drv_lcd_hw_init(void) { rt_err_t result = RT_EOK; rt_uint32_t lcd_buff_size = lcd_buff_size = LCD_HEIGHT * LCD_WIDTH * 2; /* 创建LCD设备对象 */ struct rt_device *device = &_lcd.lcd_dev; memset(&_lcd, 0x00, sizeof(_lcd)); LOG_D("drv_lcd_hw_init!n"); /* 初始化lcd_lock信号量 */ result = rt_sem_init(&_lcd.lcd_lock, "lcd_lock", 0, RT_IPC_FLAG_FIFO); if (result != RT_EOK) { LOG_E("init semaphore failed!n"); result = -RT_ENOMEM; goto __exit; } /* 设置 LCD 设备信息 */ _lcd.lcd_info.height = LCD_HEIGHT; _lcd.lcd_info.width = LCD_WIDTH; _lcd.lcd_info.bits_per_pixel = LCD_BITS_PER_PIXEL; _lcd.lcd_info.pixel_format = RTGRAPHIC_PIXEL_FORMAT_RGB565; // 图像的格式（RGB：565） /* LCD 显示缓冲区，大小为显示一帧图像所需空间 */ _lcd.lcd_info.smem_len = lcd_buff_size; _lcd.lcd_info.framebuffer = rt_malloc(lcd_buff_size); if (_lcd.lcd_info.framebuffer == RT_NULL) { LOG_E("init frame buffer failed!n"); result = -RT_ENOMEM; goto __exit; } /* 将缓冲区初始化为 0xFF */ memset(_lcd.lcd_info.framebuffer, 0xFF, lcd_buff_size); #ifdef RT_USING_DEVICE_OPS device->ops = &lcd_ops; #else device->init = drv_lcd_init; device->control = drv_lcd_control; #endif /* 注册 LCD 设备 */ rt_device_register(device, "lcd", RT_DEVICE_FLAG_RDWR); __exit: if (result != RT_EOK) { rt_sem_detach(&_lcd.lcd_lock); if (_lcd.lcd_info.framebuffer) { rt_free(_lcd.lcd_info.framebuffer); } } return result; } INIT_DEVICE_EXPORT(drv_lcd_hw_init); #endif /* BSP_USING_LCD */ 
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