STM32F4 LTDC学习

很久没有写东西了，也很久没看文档了吼吼，觉得有点无聊，找来F4看看，主要看F429。督促自己多看多记录。

首先配置同步时序先看参考手册

下面看一个实际例子，一块439的开发板

设置：

 1  LTDC_InitStruct.LTDC_HorizontalSync = 40;
 2   /*  */
 3   LTDC_InitStruct.LTDC_VerticalSync = 9;
 4   /*  */
 5   LTDC_InitStruct.LTDC_AccumulatedHBP = 42; 
 6   /*  */
 7   LTDC_InitStruct.LTDC_AccumulatedVBP = 11;  
 8   /*  */
 9   LTDC_InitStruct.LTDC_AccumulatedActiveW = 522;
10   /*  */
11   LTDC_InitStruct.LTDC_AccumulatedActiveH = 283;
12   /*  */
13   LTDC_InitStruct.LTDC_TotalWidth = 524; 
14   /*  */
15   LTDC_InitStruct.LTDC_TotalHeigh = 285;
16             
17   LTDC_Init(&LTDC_InitStruct);

配置时序

注意每个参数定义，之前是累加

看下完整的初始化代码

  1 void LCD_Init(void)
  2 {
  3   LTDC_InitTypeDef       LTDC_InitStruct;
  4   LTDC_Layer_InitTypeDef LTDC_Layer_InitStruct;
  5   LTDC_Layer_TypeDef     LTDC_Layerx;
  6   
  7     
  8   /* IO¿Ú³õÊ¼»¯ */
  9   LCD_GPIOInit();
 10     
 11   LCD_DisplayOff();
 12   /* Ê¹ÄÜLCDÊ±ÖÓ */
 13   RCC_APB2PeriphClockCmd(RCC_APB2Periph_LTDC, ENABLE);
 14   /* Ê¹ÄÜDMAÊ§×Ù*/
 15   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2D, ENABLE);
 16     
 17   /* Ë®Æ½Í¬²½ÐÅºÅ---µÍµçÆ½ÓÐÐ§ */
 18   LTDC_InitStruct.LTDC_HSPolarity = LTDC_HSPolarity_AL;     
 19   /* ´¹Ö±Í¬²½ÐÅºÅ---µÍµçÆ½ÓÐÐ§ */  
 20   LTDC_InitStruct.LTDC_VSPolarity = LTDC_VSPolarity_AL;     
 21   /* Êý¾ÝÊ¹ÄÜÐÅºÅ---µÍµçÆ½ÓÐÐ§ */
 22   LTDC_InitStruct.LTDC_DEPolarity = LTDC_DEPolarity_AL;     
 23   /* ÏñËØÊ±ÖÓÅäÖÃ--- */ 
 24   LTDC_InitStruct.LTDC_PCPolarity = LTDC_DEPolarity_AL;
 25     /* LCD±³¹âÉèÖÃ */
 26   LTDC_InitStruct.LTDC_BackgroundRedValue = 0;            
 27   LTDC_InitStruct.LTDC_BackgroundGreenValue = 0;          
 28   LTDC_InitStruct.LTDC_BackgroundBlueValue = 0;      
 29   /*
 30    ****************************************************************************
 31    *PLLSAI_VCO = HSE*PLLSAI_N / PLL_M = 8 * 192 / 8 = 192MHz
 32    *PLLLCDCLK = PLLSAI_VCO / PLLSAI_R = 192 / 3 = 64 Mhz
 33    *LTDC clock frequency = PLLLCDCLK / RCC_PLLSAIDivR = 64 / 8 = 8 Mhz
 34    ****************************************************************************
 35    */
 36   RCC_PLLSAIConfig(192, 7, 3);
 37   RCC_LTDCCLKDivConfig(RCC_PLLSAIDivR_Div4);    
 38   /* Ê¹ÄÜPLLSAIÊ±ÖÓ */
 39   RCC_PLLSAICmd(ENABLE);
 40   /* µÈ´ýPLLSAIÊ±ÖÓ */
 41   while(RCC_GetFlagStatus(RCC_FLAG_PLLSAIRDY) == RESET){}
 42   /*  */
 43   LTDC_InitStruct.LTDC_HorizontalSync = 40;
 44   /*  */
 45   LTDC_InitStruct.LTDC_VerticalSync = 9;
 46   /*  */
 47   LTDC_InitStruct.LTDC_AccumulatedHBP = 42; 
 48   /*  */
 49   LTDC_InitStruct.LTDC_AccumulatedVBP = 11;  
 50   /*  */
 51   LTDC_InitStruct.LTDC_AccumulatedActiveW = 522;
 52   /*  */
 53   LTDC_InitStruct.LTDC_AccumulatedActiveH = 283;
 54   /*  */
 55   LTDC_InitStruct.LTDC_TotalWidth = 524; 
 56   /*  */
 57   LTDC_InitStruct.LTDC_TotalHeigh = 285;
 58             
 59   LTDC_Init(&LTDC_InitStruct);
 60         
 61   LTDC_Layer_InitStruct.LTDC_HorizontalStart = 43;
 62   LTDC_Layer_InitStruct.LTDC_HorizontalStop = (480 + 43 - 1); 
 63   LTDC_Layer_InitStruct.LTDC_VarticalStart = 12;
 64   LTDC_Layer_InitStruct.LTDC_VerticalStop = (272 + 12 - 1);    
 65 
 66   /* Pixel Format configuration*/            
 67   LTDC_Layer_InitStruct.LTDC_PixelFormat = LTDC_Pixelformat_RGB565;
 68   /* Alpha constant (255 totally opaque) */
 69   LTDC_Layer_InitStruct.LTDC_ConstantAlpha = 255; 
 70   /* Default Color configuration (configure A,R,G,B component values) */          
 71   LTDC_Layer_InitStruct.LTDC_DefaultColorBlue = 0;        
 72   LTDC_Layer_InitStruct.LTDC_DefaultColorGreen = 0;       
 73   LTDC_Layer_InitStruct.LTDC_DefaultColorRed = 0;         
 74   LTDC_Layer_InitStruct.LTDC_DefaultColorAlpha = 0;
 75   /* Configure blending factors */       
 76   LTDC_Layer_InitStruct.LTDC_BlendingFactor_1 = LTDC_BlendingFactor1_CA;    
 77   LTDC_Layer_InitStruct.LTDC_BlendingFactor_2 = LTDC_BlendingFactor2_CA;
 78   /* the length of one line of pixels in bytes + 3 then :
 79      Line Lenth = Active high width x number of bytes per pixel + 3 
 80      Active high width         = LCD_PIXEL_WIDTH 
 81      number of bytes per pixel = 2    (pixel_format : RGB565) 
 82   */
 83   LTDC_Layer_InitStruct.LTDC_CFBLineLength = ((480 * 2) + 3);
 84   /*  the pitch is the increment from the start of one line of pixels to the 
 85       start of the next line in bytes, then :
 86       Pitch = Active high width x number of bytes per pixel     
 87   */ 
 88   LTDC_Layer_InitStruct.LTDC_CFBPitch = (480 * 2);
 89   /* configure the number of lines */  
 90   LTDC_Layer_InitStruct.LTDC_CFBLineNumber = 272;
 91 
 92   /* Input Address configuration */    
 93   LTDC_Layer_InitStruct.LTDC_CFBStartAdress = LCD_FRAME_BUFFER;
 94    
 95   LTDC_LayerInit(LTDC_Layer1, &LTDC_Layer_InitStruct);
 96 
 97   /* Configure Layer2 */
 98   LTDC_Layer_InitStruct.LTDC_CFBStartAdress = LCD_FRAME_BUFFER + BUFFER_OFFSET;
 99   LTDC_Layer_InitStruct.LTDC_BlendingFactor_1 = LTDC_BlendingFactor1_PAxCA;    
100   LTDC_Layer_InitStruct.LTDC_BlendingFactor_2 = LTDC_BlendingFactor2_PAxCA;
101   LTDC_LayerInit(LTDC_Layer2, &LTDC_Layer_InitStruct);
102     
103   LTDC_ReloadConfig(LTDC_IMReload);
104   
105   /* Enable foreground & background Layers */
106   LTDC_LayerCmd(LTDC_Layer1, ENABLE);
107 //  LTDC_LayerCmd(LTDC_Layer2, ENABLE);
108   LTDC_ReloadConfig(LTDC_IMReload);
109     
110   LCD_DisplayOn();
111 }

LCD_Init

LTDC_DefaultColorBlue就是背景色

每个Layer支持窗口（Window）操作，所谓Window，就是指该层的图像只有在Window区域内有效，而Window区域外则用该层的DefaultColor填充。如下图：

填色直接写内存

 1 int main (void)
 2 {
 3   uint32_t i, j;
 4   uint16_t *addr = (uint16_t *)LCD_FRAME_BUFFER;
 5     
 6     
 7   SDRAM_Init();
 8   LCD_Init();
 9     j = 0;
10   while (1) {
11         
12     for (i = 0; i < 0x2000000;i++);
13     for (i = 0; i < 480 * 272; i++) 
14     {
15       addr[i] = 1 << j;
16     }
17     j++;
18     if (j > 15)j = 0;        
19   }    
20 }

LCD display RGB