关键词：RISC-V开发板、RVB2601、WiFi&BLE，低功耗，玄铁E906,AliOS Things，RISC-V MCU，上手好用，控制，开关

1. 前言

基于RVB2601的GUI程序是利用Lvgl开源组件实现在OLED屏幕上的字符和图形显示。开发者可以利用Lvgl组件在OLED屏幕上实现Label控件显示功能。

建议在看本文之前，先详细看下RVB2601资源。本例程名为ch2601_gui_demo，可以通过CDK直接从OCC拉取。

2. 硬件配置

2.1 显示屏

RVB2601开发板采用的是OLED显示屏，位于开发板正面。

2.2 屏幕物理接口

CH2601开发板采用单彩色图形显示面板，屏幕分辨率128x64 pixel，屏幕背景颜色可选，该程序中采用的是一块黄色背景的屏幕。屏幕控制器采用SSD1309，通过4 wire SPI接口与主芯片连接, 原理图如下所示, 对应的pin引脚分别为PA27、PA28、PA29、PA30。原理图如下：

软件通过对SPI进行读写操作来实现对OLED屏上的像素进行点操作，从而实现整个屏的点亮操作。

3. GUI软件开发

3.1 LVGL介绍

LVGL全称Light and Versatile Graphics Library,是一个自由的，开源的GUI库，具有界面精美，资源消耗小，可移植度高, 响应式布局等特点, 全库采用纯 c 语言开发.

主要特性如下.

具有非常丰富的内置控件,像 buttons, charts, lists, sliders, images 等
高级图形效果：动画，反锯齿，透明度，平滑滚动
支持多种输入设备,像 touchpad, mouse, keyboard, encoder 等
支持多语言的 UTF-8 编码
支持多个和多种显示设备，例如同步显示在多个彩色屏或单色屏上
完全自定制的图形元素
硬件独立于任何微控制器或显示器
可以缩小到最小内存 (64 kB Flash, 16 kB RAM)
支持操作系统、外部储存和 GPU（非必须）
仅仅单个帧缓冲设备就可以呈现高级视觉特效
使用 C 编写以获得最大兼容性(兼容 C++)
支持 PC 模拟器
为加速 GUI 设计,提供教程,案例和主题,支持响应式布局
提供了在线和离线文档
基于自由和开源的 MIT 协议
支持MicroPython

3.2 例程下载

打开CDK，点击HOME图标，查找ch2601_gui_demo后，打开工程可以看到以下目录：

3.3 LVGL移植接口

Lvgl移植代码位于app/src/lvgl_porting文件夹内，其包含oled.c和oled.h。

以下功能接口位于app/src/lvgl_porting/oled.c，实现SPI管脚的初始化，主要针对CS, DATA, CLOCK, DATAIN管脚，同时实现了对不同管脚的读写操作。

static void oled_gpio_init()
{//csi_gpio_pin_init(&pin_clk, PA28);csi_gpio_pin_dir(&pin_clk, GPIO_DIRECTION_OUTPUT);csi_gpio_pin_init(&pin_mosi, PA29);csi_gpio_pin_dir(&pin_mosi, GPIO_DIRECTION_OUTPUT);csi_gpio_pin_init(&pin_cs, PA27);csi_gpio_pin_dir(&pin_cs, GPIO_DIRECTION_OUTPUT);csi_gpio_pin_init(&pin_miso, PA30); //dccsi_gpio_pin_dir(&pin_miso, GPIO_DIRECTION_OUTPUT);
}static void lcd_cs(uint8_t d)
{if (d == 1) {csi_gpio_pin_write(&pin_cs, GPIO_PIN_HIGH);} else {csi_gpio_pin_write(&pin_cs, GPIO_PIN_LOW);}
}static void lcd_dc(uint8_t d)
{if (d == 1) {csi_gpio_pin_write(&pin_miso, GPIO_PIN_HIGH);} else {csi_gpio_pin_write(&pin_miso, GPIO_PIN_LOW);}
}static void lcd_sclk(uint8_t d)
{if (d == 1) {csi_gpio_pin_write(&pin_clk, GPIO_PIN_HIGH);} else {csi_gpio_pin_write(&pin_clk, GPIO_PIN_LOW);}
}static void lcd_sdin(uint8_t d)
{if (d == 1) {csi_gpio_pin_write(&pin_mosi, GPIO_PIN_HIGH);} else {csi_gpio_pin_write(&pin_mosi, GPIO_PIN_LOW);}
}

以下功能函数位于app/src/lvgl_porting/oled.c，通过SPI实现对屏幕的命令和数据写操作。

void Write_Command(unsigned char Data)
{unsigned char i;lcd_cs(0);lcd_dc(0);for (i = 0; i < 8; i++) {lcd_sclk(0);lcd_sdin((Data & 0x80) >> 7);Data = Data << 1;lcd_sclk(1);}lcd_dc(1);lcd_cs(1);
}void Write_Data(unsigned char Data)
{unsigned char i;lcd_cs(0);lcd_dc(1);for (i = 0; i < 8; i++) {lcd_sclk(0);lcd_sdin((Data & 0x80) >> 7);Data = Data << 1;lcd_sclk(1);}lcd_dc(1);lcd_cs(1);
}

以下功能函数位于app/src/lvgl_porting/oled.c文件中，实现对屏幕的基本命令操作，例如设置屏幕行列地址，屏幕的亮度控制等。

void Set_Start_Column(unsigned char d)
{Write_Command(0x00 + d % 16); // Set Lower Column Start Address for Page Addressing Mode//   Default => 0x00Write_Command(0x10 + d / 16); // Set Higher Column Start Address for Page Addressing Mode//   Default => 0x10
}void Set_Addressing_Mode(unsigned char d)
{Write_Command(0x20); // Set Memory Addressing ModeWrite_Command(d);    //   Default => 0x02//     0x00 => Horizontal Addressing Mode//     0x01 => Vertical Addressing Mode//     0x02 => Page Addressing Mode
}void Set_Column_Address(unsigned char a, unsigned char b)
{Write_Command(0x21); // Set Column AddressWrite_Command(a);    //   Default => 0x00 (Column Start Address)Write_Command(b);    //   Default => 0x7F (Column End Address)
}void Set_Page_Address(unsigned char a, unsigned char b)
{Write_Command(0x22); // Set Page AddressWrite_Command(a);    //   Default => 0x00 (Page Start Address)Write_Command(b);    //   Default => 0x07 (Page End Address)
}void Set_Start_Line(unsigned char d)
{Write_Command(0x40 | d); // Set Display Start Line//   Default => 0x40 (0x00)
}void Set_Contrast_Control(unsigned char d)
{Write_Command(0x81); // Set Contrast Control for Bank 0Write_Command(d);    //   Default => 0x7F
}void Set_Segment_Remap(unsigned char d)
{Write_Command(d); // Set Segment Re-Map//   Default => 0xA0//     0xA0 => Column Address 0 Mapped to SEG0//     0xA1 => Column Address 0 Mapped to SEG127
}void Set_Entire_Display(unsigned char d)
{Write_Command(d); // Set Entire Display On / Off//   Default => 0xA4//     0xA4 => Normal Display//     0xA5 => Entire Display On
}void Set_Inverse_Display(unsigned char d)
{Write_Command(d); // Set Inverse Display On/Off//   Default => 0xA6//     0xA6 => Normal Display//     0xA7 => Inverse Display On
}void Set_Multiplex_Ratio(unsigned char d)
{Write_Command(0xA8); // Set Multiplex RatioWrite_Command(d);    //   Default => 0x3F (1/64 Duty)
}void Set_Display_On_Off(unsigned char d)
{Write_Command(d); // Set Display On/Off//   Default => 0xAE//     0xAE => Display Off//     0xAF => Display On
}void Set_Start_Page(unsigned char d)
{Write_Command(0xB0 | d); // Set Page Start Address for Page Addressing Mode//   Default => 0xB0 (0x00)
}void Set_Common_Remap(unsigned char d)
{Write_Command(d); // Set COM Output Scan Direction//   Default => 0xC0//     0xC0 => Scan from COM0 to 63//     0xC8 => Scan from COM63 to 0
}void Set_Display_Offset(unsigned char d)
{Write_Command(0xD3); // Set Display OffsetWrite_Command(d);    //   Default => 0x00
}void Set_Display_Clock(unsigned char d)
{Write_Command(0xD5); // Set Display Clock Divide Ratio / Oscillator FrequencyWrite_Command(d);    //   Default => 0x70//     D[3:0] => Display Clock Divider//     D[7:4] => Oscillator Frequency
}void Set_Low_Power(unsigned char d)
{Write_Command(0xD8); // Set Low Power Display ModeWrite_Command(d);    //   Default => 0x04 (Normal Power Mode)
}void Set_Precharge_Period(unsigned char d)
{Write_Command(0xD9); // Set Pre-Charge PeriodWrite_Command(d); //   Default => 0x22 (2 Display Clocks [Phase 2] / 2 Display Clocks [Phase 1])//     D[3:0] => Phase 1 Period in 1~15 Display Clocks//     D[7:4] => Phase 2 Period in 1~15 Display Clocks
}void Set_Common_Config(unsigned char d)
{Write_Command(0xDA); // Set COM Pins Hardware ConfigurationWrite_Command(d);    //   Default => 0x12//     Alternative COM Pin Configuration//     Disable COM Left/Right Re-Map
}void Set_NOP()
{Write_Command(0xE3); // Command for No Operation
}void Set_Command_Lock(unsigned char d)
{Write_Command(0xFD); // Set Command LockWrite_Command(d);    //   Default => 0x12//     0x12 => Driver IC interface is unlocked from entering command.//     0x16 => All Commands are locked except 0xFD.
}

该功能函数位于app/src/lvgl_porting/oled.c文件中，实现对屏幕的初始化。

static void oled_initialize()
{Set_Command_Lock(0x12);           // Unlock Driver IC (0x12/0x16)Set_Display_On_Off(0xAE);         // Display Off (0xAE/0xAF)Set_Display_Clock(0xA0);          // Set Clock as 116 Frames/SecSet_Multiplex_Ratio(0x3F);        // 1/64 Duty (0x0F~0x3F)Set_Display_Offset(0x00);         // Shift Mapping RAM Counter (0x00~0x3F)Set_Start_Line(0x00);             // Set Mapping RAM Display Start Line (0x00~0x3F)Set_Low_Power(0x04);              // Set Normal Power Mode (0x04/0x05)Set_Addressing_Mode(0x02);        // Set Page Addressing Mode (0x00/0x01/0x02)Set_Segment_Remap(0xA1);          // Set SEG/Column Mapping (0xA0/0xA1)Set_Common_Remap(0xC8);           // Set COM/Row Scan Direction (0xC0/0xC8)Set_Common_Config(0x12);          // Set Alternative Configuration (0x02/0x12)Set_Contrast_Control(Brightness); // Set SEG Output CurrentSet_Precharge_Period(0x82);       // Set Pre-Charge as 8 Clocks & Discharge as 2 ClocksSet_VCOMH(0x34);                  // Set VCOM Deselect LevelSet_Entire_Display(0xA4);         // Disable Entire Display On (0xA4/0xA5)Set_Inverse_Display(0xA6);        // Disable Inverse Display On (0xA6/0xA7)Fill_RAM(0x00); // Clear ScreenSet_Display_On_Off(0xAF); // Display On (0xAE/0xAF)
}

该功能函数位于app/src/main.c文件中，实现在屏幕固定处画一个label, 显示一串字符串。

static void gui_label_create(void)
{lv_obj_t *p = lv_label_create(lv_scr_act(), NULL);lv_label_set_long_mode(p, LV_LABEL_LONG_BREAK);lv_label_set_align(p, LV_LABEL_ALIGN_CENTER);lv_obj_set_pos(p, 0, 4);lv_obj_set_size(p, 128, 60);lv_label_set_text(p, "THEAD RISC-V\nGUI\nDEMO");
}