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：

  LTDC_InitStruct.LTDC_HorizontalSync = ;
   /*  */
   LTDC_InitStruct.LTDC_VerticalSync = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedHBP = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedVBP = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedActiveW = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedActiveH = ;
   /*  */
   LTDC_InitStruct.LTDC_TotalWidth = ;
   /*  */
   LTDC_InitStruct.LTDC_TotalHeigh = ;

   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

 void LCD_Init(void)
 {
   LTDC_InitTypeDef       LTDC_InitStruct;
   LTDC_Layer_InitTypeDef LTDC_Layer_InitStruct;
   LTDC_Layer_TypeDef     LTDC_Layerx;

   /* IO¿Ú³õʼ»¯ */
   LCD_GPIOInit();

   LCD_DisplayOff();
   /* ʹÄÜLCDʱÖÓ */
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_LTDC, ENABLE);
   /* ʹÄÜDMAʧ×Ù*/
   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2D, ENABLE);

   /* ˮƽͬ²½ÐźÅ---µÍµçƽÓÐЧ */
   LTDC_InitStruct.LTDC_HSPolarity = LTDC_HSPolarity_AL;
   /* ´¹Ö±Í¬²½ÐźÅ---µÍµçƽÓÐЧ */
   LTDC_InitStruct.LTDC_VSPolarity = LTDC_VSPolarity_AL;
   /* Êý¾ÝʹÄÜÐźÅ---µÍµçƽÓÐЧ */
   LTDC_InitStruct.LTDC_DEPolarity = LTDC_DEPolarity_AL;
   /* ÏñËØʱÖÓÅäÖÃ--- */
   LTDC_InitStruct.LTDC_PCPolarity = LTDC_DEPolarity_AL;
     /* LCD±³¹âÉèÖà */
   LTDC_InitStruct.LTDC_BackgroundRedValue = ;
   LTDC_InitStruct.LTDC_BackgroundGreenValue = ;
   LTDC_InitStruct.LTDC_BackgroundBlueValue = ;
   /*
    ****************************************************************************
    *PLLSAI_VCO = HSE*PLLSAI_N / PLL_M = 8 * 192 / 8 = 192MHz
    *PLLLCDCLK = PLLSAI_VCO / PLLSAI_R = 192 / 3 = 64 Mhz
    *LTDC clock frequency = PLLLCDCLK / RCC_PLLSAIDivR = 64 / 8 = 8 Mhz
    ****************************************************************************
    */
   RCC_PLLSAIConfig(, , );
   RCC_LTDCCLKDivConfig(RCC_PLLSAIDivR_Div4);
   /* ʹÄÜPLLSAIʱÖÓ */
   RCC_PLLSAICmd(ENABLE);
   /* µÈ´ýPLLSAIʱÖÓ */
   while(RCC_GetFlagStatus(RCC_FLAG_PLLSAIRDY) == RESET){}
   /*  */
   LTDC_InitStruct.LTDC_HorizontalSync = ;
   /*  */
   LTDC_InitStruct.LTDC_VerticalSync = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedHBP = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedVBP = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedActiveW = ;
   /*  */
   LTDC_InitStruct.LTDC_AccumulatedActiveH = ;
   /*  */
   LTDC_InitStruct.LTDC_TotalWidth = ;
   /*  */
   LTDC_InitStruct.LTDC_TotalHeigh = ;

   LTDC_Init(&LTDC_InitStruct);

   LTDC_Layer_InitStruct.LTDC_HorizontalStart = ;
   LTDC_Layer_InitStruct.LTDC_HorizontalStop = ( +  - );
   LTDC_Layer_InitStruct.LTDC_VarticalStart = ;
   LTDC_Layer_InitStruct.LTDC_VerticalStop = ( +  - );    

   /* Pixel Format configuration*/
   LTDC_Layer_InitStruct.LTDC_PixelFormat = LTDC_Pixelformat_RGB565;
   /* Alpha constant (255 totally opaque) */
   LTDC_Layer_InitStruct.LTDC_ConstantAlpha = ;
   /* Default Color configuration (configure A,R,G,B component values) */
   LTDC_Layer_InitStruct.LTDC_DefaultColorBlue = ;
   LTDC_Layer_InitStruct.LTDC_DefaultColorGreen = ;
   LTDC_Layer_InitStruct.LTDC_DefaultColorRed = ;
   LTDC_Layer_InitStruct.LTDC_DefaultColorAlpha = ;
   /* Configure blending factors */
   LTDC_Layer_InitStruct.LTDC_BlendingFactor_1 = LTDC_BlendingFactor1_CA;
   LTDC_Layer_InitStruct.LTDC_BlendingFactor_2 = LTDC_BlendingFactor2_CA;
   /* the length of one line of pixels in bytes + 3 then :
      Line Lenth = Active high width x number of bytes per pixel + 3
      Active high width         = LCD_PIXEL_WIDTH
      number of bytes per pixel = 2    (pixel_format : RGB565)
   */
   LTDC_Layer_InitStruct.LTDC_CFBLineLength = (( * ) + );
   /*  the pitch is the increment from the start of one line of pixels to the
       start of the next line in bytes, then :
       Pitch = Active high width x number of bytes per pixel
   */
   LTDC_Layer_InitStruct.LTDC_CFBPitch = ( * );
   /* configure the number of lines */
   LTDC_Layer_InitStruct.LTDC_CFBLineNumber = ;

   /* Input Address configuration */
   LTDC_Layer_InitStruct.LTDC_CFBStartAdress = LCD_FRAME_BUFFER;

   LTDC_LayerInit(LTDC_Layer1, &LTDC_Layer_InitStruct);

   /* Configure Layer2 */
   LTDC_Layer_InitStruct.LTDC_CFBStartAdress = LCD_FRAME_BUFFER + BUFFER_OFFSET;
   LTDC_Layer_InitStruct.LTDC_BlendingFactor_1 = LTDC_BlendingFactor1_PAxCA;
   LTDC_Layer_InitStruct.LTDC_BlendingFactor_2 = LTDC_BlendingFactor2_PAxCA;
   LTDC_LayerInit(LTDC_Layer2, &LTDC_Layer_InitStruct);

   LTDC_ReloadConfig(LTDC_IMReload);

   /* Enable foreground & background Layers */
   LTDC_LayerCmd(LTDC_Layer1, ENABLE);
 //  LTDC_LayerCmd(LTDC_Layer2, ENABLE);
   LTDC_ReloadConfig(LTDC_IMReload);

   LCD_DisplayOn();
 }

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

 int main (void)
 {
   uint32_t i, j;
   uint16_t *addr = (uint16_t *)LCD_FRAME_BUFFER;

   SDRAM_Init();
   LCD_Init();
     j = ;
   while () {

     for (i = ; i < 0x2000000;i++);
     for (i = ; i <  * ; i++)
     {
       addr[i] =  << j;
     }
     j++;
     if (j > )j = ;
   }
 }

LCD display RGB