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MIPI 系列之 DCS

阅读数 4

1、Display Architectures

2、Power Level Definition

3、Display Command Set

4、Command List

5、Command Accessibility

6、Default Modes and Values

7、Command Descriptions

7.1、enter_idle_mode

7.2、set_page_address

7.3、set_column_address

MIPI 协议族，定义了一个专门用于显示的命令集，叫做 Display Command Set，简称为 DCS；这个 DCS 起什么作用呢？主要是 Host 和 Display 之间的一些 Command 配置和数据传输，以及读 Display 的数据等；

使用过 SPI 的屏的朋友们应该知道，上电后，就开始劈里啪啦的一顿配置，比如，SPI 的屏 ST7735S，上电初始化，就是一顿干：


static void LCD_Parameters_Init(void)
{
    LCD_RST_LOW();// Reset
    delay_ms(100);
    LCD_RST_HIGH();
    delay_ms(100);
 
    LCD_BLK_HIGH();// Open bl
    delay_ms(100);
    LCD_WriteCmd(0x11); // Sleep out
    delay_ms(120);    // Delay 120ms
    //------------------------------------ST7735S Frame rate-------------------------------------------------//
    LCD_WriteCmd(0xB1); //Frame rate 80Hz
    LCD_WriteData(0x02);
    LCD_WriteData(0x35);
    LCD_WriteData(0x36);
 
    LCD_WriteCmd(0xB2); //Frame rate 80Hz
    LCD_WriteData(0x02);
    LCD_WriteData(0x35);
    LCD_WriteData(0x36);
 
    LCD_WriteCmd(0xB3); //Frame rate 80Hz
    LCD_WriteData(0x02);
    LCD_WriteData(0x35);
    LCD_WriteData(0x36);
    LCD_WriteData(0x02);
    LCD_WriteData(0x35);
    LCD_WriteData(0x36);
    //------------------------------------End ST7735S Frame rate-------------------------------------------//
    LCD_WriteCmd(0xB4); //Dot inversion
    LCD_WriteData(0x03);
    //------------------------------------ST7735S Power Sequence-----------------------------------------//
    LCD_WriteCmd(0xC0);
    LCD_WriteData(0xA2);
    LCD_WriteData(0x02);
    LCD_WriteData(0x84);
 
    LCD_WriteCmd(0xC1);
    LCD_WriteData(0xC5);
 
    LCD_WriteCmd(0xC2);
    LCD_WriteData(0x0D);
    LCD_WriteData(0x00);
 
    LCD_WriteCmd(0xC3);
    LCD_WriteData(0x8D);
    LCD_WriteData(0x2A);
 
    LCD_WriteCmd(0xC4);
    LCD_WriteData(0x8D);
    LCD_WriteData(0xEE);
    //---------------------------------End ST7735S Power Sequence---------------------------------------//
    LCD_WriteCmd(0xC5); //VCOM
    LCD_WriteData(0x0a);
 
    LCD_WriteCmd(0x36);
    LCD_WriteData(0x08);
    //------------------------------------ST7735S Gamma Sequence-----------------------------------------//
    LCD_WriteCmd(0XE0);
    LCD_WriteData(0x12);
    LCD_WriteData(0x1C);
    LCD_WriteData(0x10);
    LCD_WriteData(0x18);
    LCD_WriteData(0x33);
    LCD_WriteData(0x2C);
    LCD_WriteData(0x25);
    LCD_WriteData(0x28);
    LCD_WriteData(0x28);
    LCD_WriteData(0x27);
    LCD_WriteData(0x2F);
    LCD_WriteData(0x3C);
    LCD_WriteData(0x00);
    LCD_WriteData(0x03);
    LCD_WriteData(0x03);
    LCD_WriteData(0x10);
 
    LCD_WriteCmd(0XE1);
    LCD_WriteData(0x12);
    LCD_WriteData(0x1C);
    LCD_WriteData(0x10);
    LCD_WriteData(0x18);
    LCD_WriteData(0x2D);
    LCD_WriteData(0x28);
    LCD_WriteData(0x23);
    LCD_WriteData(0x28);
    LCD_WriteData(0x28);
    LCD_WriteData(0x26);
    LCD_WriteData(0x2F);
    LCD_WriteData(0x3B);
    LCD_WriteData(0x00);
    LCD_WriteData(0x03);
    LCD_WriteData(0x03);
    LCD_WriteData(0x10);
    //------------------------------------End ST7735S Gamma Sequence-----------------------------------------//
    LCD_WriteCmd(0x3A); //65k mode
    LCD_WriteData(0x05);
    LCD_WriteCmd(0x29); //Display on
}cpp
运行

可以看到，一般是一个 Command 带一堆 Data，Command 描述了这次传输是用来干嘛的，Data 呢，就是此次事件的数据；

为了标准化显示设备，所以呢，就有制定一些个标准（听君一席话，如听一席话）；

为了统一江山，Display 方，大家按照同一套标准来定制这个 Command + Data，此刻 DCS 闪亮登场；

1、Display Architectures

Display 的结构，DCS 中分为了 3 类；

可以看到，这三类的区别就是中间 Display Module 是否带了 Framebuffer，或是带了一部分的 Framebuffer；

Display Module 带不带 Framebuffer 有啥区别呢？如果带了 Framebuffer，那么图形数据不用每次都从主机获取，主机刷一次数据到 Display Module 的 Framebuffer 中，然后 Display Module 就自己会将它自己的 Framebuffer 往屏(Panel)上面刷；

如果 Display Module 不带 Framebuffer，为了维持屏上有数据，需要主机不停的给 Display Module 灌数据，并显示到 panel 上；