RVB2601应用开发实战系列三: GUI图形显示

作者阿里云代理 文章分类 分类:linux图文教程 阅读次数 已被围观 901

编辑语:

技术解码栏目:是面向开发者详细解读芯片开放社区(OCC)上关于处理器、芯片、基础软件平台、集成开发环境及应用开发平台的相关技术,方便开发者学习及快速上手,提升开发效率。

. 前言

RVB2601基于平头哥RISC-V生态芯片的开发套件,开发者基于RVB2601可进行端云一体的物联网应用开发及音频方案开发。上周向大家推荐了RVB2601应用开发实战系列二: 跑马灯实例教程,基于RVB2601GUI程序是利用Lvgl开源组件实现在TFT LCD屏幕上做字符和图形显示。开发者可以利用Lvgl组件在TFT LCD屏幕上实现Label空间显示功能。

建议在看本文之前,先详细看下新手必看 | RVB2601开发板快速上手指南。本例程名为ch2601_gui_demo,可以通过集成开发环境剑池CDK下载获取相应资源。

. 硬件配置

2.1 显示屏

RVB2601开发板采用的是TFT LCD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PA27PA28PA29PA30。原理图如下:

软件通过对SPI进行读写操作来实现,对TFT LCD屏上的像素进行点缀操作,从而实现整个屏的点亮操作。

. 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,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,buttons, charts, lists, sliders, images

· 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,touchpad, mouse, keyboard, encoder

· 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,打开工程可以看下一下目录文件:

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.coled.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教的读写操作。

1. static void oled_gpio_init()2. {3. //4. csi_gpio_pin_init(&pin_clk, PA28);5. csi_gpio_pin_dir(&pin_clk, GPIO_DIRECTION_OUTPUT);6. csi_gpio_pin_init(&pin_mosi, PA29);7. csi_gpio_pin_dir(&pin_mosi, GPIO_DIRECTION_OUTPUT);8. csi_gpio_pin_init(&pin_cs, PA27);9. csi_gpio_pin_dir(&pin_cs, GPIO_DIRECTION_OUTPUT);10. csi_gpio_pin_init(&pin_miso, PA30); //dc11. csi_gpio_pin_dir(&pin_miso, GPIO_DIRECTION_OUTPUT);12. }13. 14. static void lcd_cs(uint8_t d)15. {16. if (d == 1) {17. csi_gpio_pin_write(&pin_cs, GPIO_PIN_HIGH);18. } else {19. csi_gpio_pin_write(&pin_cs, GPIO_PIN_LOW);20. }21. }22. 23. static void lcd_dc(uint8_t d)24. {25. if (d == 1) {26. csi_gpio_pin_write(&pin_miso, GPIO_PIN_HIGH);27. } else {28. csi_gpio_pin_write(&pin_miso, GPIO_PIN_LOW);29. }30. }31. 32. static void lcd_sclk(uint8_t d)33. {34. if (d == 1) {35. csi_gpio_pin_write(&pin_clk, GPIO_PIN_HIGH);36. } else {37. csi_gpio_pin_write(&pin_clk, GPIO_PIN_LOW);38. }39. }40. 41. static void lcd_sdin(uint8_t d)42. {43. if (d == 1) {44. csi_gpio_pin_write(&pin_mosi, GPIO_PIN_HIGH);45. } else {46. csi_gpio_pin_write(&pin_mosi, GPIO_PIN_LOW);47. }48. }c

· 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。

1. void Write_Command(unsigned char Data)2. {3. unsigned char i;4. 5. lcd_cs(0);6. lcd_dc(0);7. for (i = 0; i < 8; i++) {8. lcd_sclk(0);9. lcd_sdin((Data & 0x80) >> 7);10. Data = Data << 1;11. lcd_sclk(1);12. }13. lcd_dc(1);14. lcd_cs(1);15. }16. 17. void Write_Data(unsigned char Data)18. {19. unsigned char i;20. 21. lcd_cs(0);22. lcd_dc(1);23. for (i = 0; i < 8; i++) {24. lcd_sclk(0);25. lcd_sdin((Data & 0x80) >> 7);26. Data = Data << 1;27. lcd_sclk(1);28. }29. lcd_dc(1);30. lcd_cs(1);31. }c

· 以下功能函数位于app/src/lvgl_porting/oled.c,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。

1. void Set_Start_Column(unsigned char d)2. {3. Write_Command(0x00 + d % 16); // Set Lower Column Start Address for Page Addressing Mode4. //   Default => 0x005. Write_Command(0x10 + d / 16); // Set Higher Column Start Address for Page Addressing Mode6. //   Default => 0x107. }8. 9. void Set_Addressing_Mode(unsigned char d)10. {11. Write_Command(0x20); // Set Memory Addressing Mode12. Write_Command(d);    //   Default => 0x0213. //     0x00 => Horizontal Addressing Mode14. //     0x01 => Vertical Addressing Mode15. //     0x02 => Page Addressing Mode16. }17. 18. void Set_Column_Address(unsigned char a, unsigned char b)19. {20. Write_Command(0x21); // Set Column Address21. Write_Command(a);    //   Default => 0x00 (Column Start Address)22. Write_Command(b);    //   Default => 0x7F (Column End Address)23. }24. 25. void Set_Page_Address(unsigned char a, unsigned char b)26. {27. Write_Command(0x22); // Set Page Address28. Write_Command(a);    //   Default => 0x00 (Page Start Address)29. Write_Command(b);    //   Default => 0x07 (Page End Address)30. }31. 32. void Set_Start_Line(unsigned char d)33. {34. Write_Command(0x40 | d); // Set Display Start Line35. //   Default => 0x40 (0x00)36. }37. 38. void Set_Contrast_Control(unsigned char d)39. {40. Write_Command(0x81); // Set Contrast Control for Bank 041. Write_Command(d);    //   Default => 0x7F42. }43. 44. void Set_Segment_Remap(unsigned char d)45. {46. Write_Command(d); // Set Segment Re-Map47. //   Default => 0xA048. //     0xA0 => Column Address 0 Mapped to SEG049. //     0xA1 => Column Address 0 Mapped to SEG12750. }51. 52. void Set_Entire_Display(unsigned char d)53. {54. Write_Command(d); // Set Entire Display On / Off55. //   Default => 0xA456. //     0xA4 => Normal Display57. //     0xA5 => Entire Display On58. }59. 60. void Set_Inverse_Display(unsigned char d)61. {62. Write_Command(d); // Set Inverse Display On/Off63. //   Default => 0xA664. //     0xA6 => Normal Display65. //     0xA7 => Inverse Display On66. }67. 68. void Set_Multiplex_Ratio(unsigned char d)69. {70. Write_Command(0xA8); // Set Multiplex Ratio71. Write_Command(d);    //   Default => 0x3F (1/64 Duty)72. }73. 74. void Set_Display_On_Off(unsigned char d)75. {76. Write_Command(d); // Set Display On/Off77. //   Default => 0xAE78. //     0xAE => Display Off79. //     0xAF => Display On80. }81. 82. void Set_Start_Page(unsigned char d)83. {84. Write_Command(0xB0 | d); // Set Page Start Address for Page Addressing Mode85. //   Default => 0xB0 (0x00)86. }87. 88. void Set_Common_Remap(unsigned char d)89. {90. Write_Command(d); // Set COM Output Scan Direction91. //   Default => 0xC092. //     0xC0 => Scan from COM0 to 6393. //     0xC8 => Scan from COM63 to 094. }95. 96. void Set_Display_Offset(unsigned char d)97. {98. Write_Command(0xD3); // Set Display Offset99. Write_Command(d);    //   Default => 0x00100. }101. 102. void Set_Display_Clock(unsigned char d)103. {104. Write_Command(0xD5); // Set Display Clock Divide Ratio / Oscillator Frequency105. Write_Command(d);    //   Default => 0x70106. //     D[3:0] => Display Clock Divider107. //     D[7:4] => Oscillator Frequency108. }109. 110. void Set_Low_Power(unsigned char d)111. {112. Write_Command(0xD8); // Set Low Power Display Mode113. Write_Command(d);    //   Default => 0x04 (Normal Power Mode)114. }115. 116. void Set_Precharge_Period(unsigned char d)117. {118. Write_Command(0xD9); // Set Pre-Charge Period119. Write_Command(d); //   Default => 0x22 (2 Display Clocks [Phase 2] / 2 Display Clocks [Phase 1])120. //     D[3:0] => Phase 1 Period in 1~15 Display Clocks121. //     D[7:4] => Phase 2 Period in 1~15 Display Clocks122. }123. 124. void Set_Common_Config(unsigned char d)125. {126. Write_Command(0xDA); // Set COM Pins Hardware Configuration127. Write_Command(d);    //   Default => 0x12128. //     Alternative COM Pin Configuration129. //     Disable COM Left/Right Re-Map130. }131. 132. void Set_VCOMH(unsigned char d)133. {134. Write_Command(0xDB); // Set VCOMH Deselect Level135. Write_Command(d);    //   Default => 0x34 (0.78*VCC)136. }137. 138. void Set_NOP()139. {140. Write_Command(0xE3); // Command for No Operation141. }142. 143. void Set_Command_Lock(unsigned char d)144. {145. Write_Command(0xFD); // Set Command Lock146. Write_Command(d);    //   Default => 0x12147. //     0x12 => Driver IC interface is unlocked from entering command.148. //     0x16 => All Commands are locked except 0xFD.149. }c

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

1. static void oled_initialize()2. {3. Set_Command_Lock(0x12);           // Unlock Driver IC (0x12/0x16)4. Set_Display_On_Off(0xAE);         // Display Off (0xAE/0xAF)5. Set_Display_Clock(0xA0);          // Set Clock as 116 Frames/Sec6. Set_Multiplex_Ratio(0x3F);        // 1/64 Duty (0x0F~0x3F)7. Set_Display_Offset(0x00);         // Shift Mapping RAM Counter (0x00~0x3F)8. Set_Start_Line(0x00);             // Set Mapping RAM Display Start Line (0x00~0x3F)9. Set_Low_Power(0x04);              // Set Normal Power Mode (0x04/0x05)10. Set_Addressing_Mode(0x02);        // Set Page Addressing Mode (0x00/0x01/0x02)11. Set_Segment_Remap(0xA1);          // Set SEG/Column Mapping (0xA0/0xA1)12. Set_Common_Remap(0xC8);           // Set COM/Row Scan Direction (0xC0/0xC8)13. Set_Common_Config(0x12);          // Set Alternative Configuration (0x02/0x12)14. Set_Contrast_Control(Brightness); // Set SEG Output Current15. Set_Precharge_Period(0x82);       // Set Pre-Charge as 8 Clocks & Discharge as 2 Clocks16. Set_VCOMH(0x34);                  // Set VCOM Deselect Level17. Set_Entire_Display(0xA4);         // Disable Entire Display On (0xA4/0xA5)18. Set_Inverse_Display(0xA6);        // Disable Inverse Display On (0xA6/0xA7)19. 20. Fill_RAM(0x00); // Clear Screen21. 22. Set_Display_On_Off(0xAF); // Display On (0xAE/0xAF)23. }c

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

1. static void gui_label_create(void)2. {3. lv_obj_t *p = lv_label_create(lv_scr_act(), NULL);4. lv_label_set_long_mode(p, LV_LABEL_LONG_BREAK);5. lv_label_set_align(p, LV_LABEL_ALIGN_CENTER);6. lv_obj_set_pos(p, 0, 4);7. lv_obj_set_size(p, 128, 60);8. lv_label_set_text(p, "THEAD RISC-V\nGUI\nDEMO");9. }c

3.4. 编译运行

编译通过后,点击下载成功,复位运行。可看屏上显示"THEAD RISC-V\nGUI\nDEMO" 字符串。

. 总结

本例程介绍了如何通过SPI接口来实现对TFT LCD屏幕的图形显示。后续还有更多的开发例程,敬请期待!

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