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Interfacing STM32F429DISCO with a different LCD

Question asked by Lori B. on Oct 13, 2014
Latest reply on Oct 14, 2014 by Lori B.
Hi everybody! I'm working on a project based on the STM32F429DISCO  board.
I need to interface it with a bigger lcd. I developed a board to interface the STM32F429DISCO  with the LCD using the same pins of the 24bit interface.
I'm now trying to adapt the project, but I can't get the display to perform properly. I only get noisy horizontal lines. I tought I was enough to change the resolution and the timing setting of the LTDC periph, but I'm missing something for sure. I can't understand what it is.
This is the LCD:  http://www.schurter.it/Downloads/Datasheet/KWH043ST12-F03%20V.2.PDF
And this is what I changed in my code (in the stm32f429i_discovery_lcd.c file).
#define HBP  2
#define VBP  2
#define HSW  41
#define VSW  10
#define HFP 2
#define VFP  2
#define XSIZE_PHYS 480
#define YSIZE_PHYS 272
/**
  * @brief  Initializes the LCD.
  * @param  None
  * @retval None
  */
void LCD_Init(void)
{
  LTDC_InitTypeDef       LTDC_InitStruct;
  GPIO_InitTypeDef       GPIO_InitStructure;
   
  /* Enable clock for NCS port */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
   
  /* Configure NCS in Output Push-Pull mode */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOD, &GPIO_InitStructure);
   
  /* Configure the LCD Control pins ------------------------------------------*/
  LCD_CtrlLinesConfig();
  LCD_ChipSelect(DISABLE);
  LCD_ChipSelect(ENABLE);
   
  /* Configure the LCD_SPI interface -----------------------------------------*/
  LCD_SPIConfig();
   
  /* Power on the LCD --------------------------------------------------------*/
  LCD_PowerOn();
   
  /* Enable the LTDC Clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_LTDC, ENABLE);
   
  /* Enable the DMA2D Clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2D, ENABLE);
   
  /* Configure the LCD Control pins */
  LCD_AF_GPIOConfig(); 
   
  /* Configure the FMC Parallel interface : SDRAM is used as Frame Buffer for LCD */
  SDRAM_Init();
   
  /* LTDC Configuration *********************************************************/ 
  /* Polarity configuration */
  /* Initialize the horizontal synchronization polarity as active low */
  LTDC_InitStruct.LTDC_HSPolarity = LTDC_HSPolarity_AL;    
  /* Initialize the vertical synchronization polarity as active low */ 
  LTDC_InitStruct.LTDC_VSPolarity = LTDC_VSPolarity_AL;    
  /* Initialize the data enable polarity as active low */
  LTDC_InitStruct.LTDC_DEPolarity = LTDC_DEPolarity_AL;    
  /* Initialize the pixel clock polarity as input pixel clock */
  LTDC_InitStruct.LTDC_PCPolarity = LTDC_PCPolarity_IPC;
   
  /* Configure R,G,B component values for LCD background color */                  
  LTDC_InitStruct.LTDC_BackgroundRedValue = 0;           
  LTDC_InitStruct.LTDC_BackgroundGreenValue = 0;         
  LTDC_InitStruct.LTDC_BackgroundBlueValue = 0; 
   
  /* Configure PLLSAI prescalers for LCD */
  /* Enable Pixel Clock */
  /* PLLSAI_VCO Input = HSE_VALUE/PLL_M = 1 Mhz */
  /* PLLSAI_VCO Output = PLLSAI_VCO Input * PLLSAI_N = 192 Mhz */
  /* PLLLCDCLK = PLLSAI_VCO Output/PLLSAI_R = 192/4 = 48 Mhz */
  /* LTDC clock frequency = PLLLCDCLK / RCC_PLLSAIDivR = 48/8 = 6 Mhz */
  RCC_PLLSAIConfig(192, 7, 4);
  RCC_LTDCCLKDivConfig(RCC_PLLSAIDivR_Div8);
   
  /* Enable PLLSAI Clock */
  RCC_PLLSAICmd(ENABLE);
  /* Wait for PLLSAI activation */
  while(RCC_GetFlagStatus(RCC_FLAG_PLLSAIRDY) == RESET)
  {
  }
  
    /* Configure horizontal synchronization width */    
  LTDC_InitStruct.LTDC_HorizontalSync = HSW;
  /* Configure vertical synchronization height */
  LTDC_InitStruct.LTDC_VerticalSync = VSW;
  /* Configure accumulated horizontal back porch */
  LTDC_InitStruct.LTDC_AccumulatedHBP = HSW + HBP;
  /* Configure accumulated vertical back porch */
  LTDC_InitStruct.LTDC_AccumulatedVBP = VSW + VBP; 
  /* Configure accumulated active width */ 
  LTDC_InitStruct.LTDC_AccumulatedActiveW = HSW + HBP + XSIZE_PHYS;
  /* Configure accumulated active height */
  LTDC_InitStruct.LTDC_AccumulatedActiveH = VSW + VBP + YSIZE_PHYS;
  /* Configure total width */
  LTDC_InitStruct.LTDC_TotalWidth = HSW + HBP + XSIZE_PHYS + HFP;
  /* Configure total height */
  LTDC_InitStruct.LTDC_TotalHeigh = VSW + VBP + YSIZE_PHYS + VFP;
   
  LTDC_Init(<DC_InitStruct);
 
 
/**
  * @brief  Initializes the LCD Layers.
  * @param  None
  * @retval None
  */
void LCD_LayerInit(void)
{
  LTDC_Layer_InitTypeDef LTDC_Layer_InitStruct;
   
  /* Windowing configuration */
  /* In this case all the active display area is used to display a picture then :
  Horizontal start = horizontal synchronization + Horizontal back porch = 30
  Horizontal stop = Horizontal start + window width -1 = 30 + 490 -1
  Vertical start   = vertical synchronization + vertical back porch     = 4
  Vertical stop   = Vertical start + window height -1  = 4 + 320 -1      */ 
    
    LTDC_Layer_InitStruct.LTDC_HorizontalStart = HBP + 1;
  LTDC_Layer_InitStruct.LTDC_HorizontalStop  = (LCD_PIXEL_WIDTH + HBP);
  LTDC_Layer_InitStruct.LTDC_VerticalStart   = VBP + 1;
  LTDC_Layer_InitStruct.LTDC_VerticalStop    = (LCD_PIXEL_HEIGHT + VBP);

  /* Pixel Format configuration*/
  LTDC_Layer_InitStruct.LTDC_PixelFormat = LTDC_Pixelformat_RGB565;
  /* Alpha constant (255 totally opaque) */
  LTDC_Layer_InitStruct.LTDC_ConstantAlpha = 255;
  /* Default Color configuration (configure A,R,G,B component values) */         
  LTDC_Layer_InitStruct.LTDC_DefaultColorBlue = 0;       
  LTDC_Layer_InitStruct.LTDC_DefaultColorGreen = 0;      
  LTDC_Layer_InitStruct.LTDC_DefaultColorRed = 0;        
  LTDC_Layer_InitStruct.LTDC_DefaultColorAlpha = 0;
  /* 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 = ((LCD_PIXEL_WIDTH * 2) + 3);
  /* 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 = (LCD_PIXEL_WIDTH * 2);
   
  /* Configure the number of lines */ 
  LTDC_Layer_InitStruct.LTDC_CFBLineNumber = LCD_PIXEL_HEIGHT;
   
  /* Start Address configuration : the LCD Frame buffer is defined on SDRAM */   
  LTDC_Layer_InitStruct.LTDC_CFBStartAdress = LCD_FRAME_BUFFER;
   
  /* Initialize LTDC layer 1 */
  LTDC_LayerInit(LTDC_Layer1, <DC_Layer_InitStruct);
   
  /* Configure Layer2 */
  /* Start Address configuration : the LCD Frame buffer is defined on SDRAM w/ Offset */    
  LTDC_Layer_InitStruct.LTDC_CFBStartAdress = LCD_FRAME_BUFFER + BUFFER_OFFSET;
   
  /* Configure blending factors */      
  LTDC_Layer_InitStruct.LTDC_BlendingFactor_1 = LTDC_BlendingFactor1_PAxCA;   
  LTDC_Layer_InitStruct.LTDC_BlendingFactor_2 = LTDC_BlendingFactor2_PAxCA;
   
  /* Initialize LTDC layer 2 */
  LTDC_LayerInit(LTDC_Layer2, <DC_Layer_InitStruct);
   
  /* LTDC configuration reload */ 
  LTDC_ReloadConfig(LTDC_IMReload);
   
  /* Enable foreground & background Layers */
  LTDC_LayerCmd(LTDC_Layer1, ENABLE);
  LTDC_LayerCmd(LTDC_Layer2, ENABLE);
   
  /* LTDC configuration reload */ 
  LTDC_ReloadConfig(LTDC_IMReload);
   
  /* Set default font */   
  LCD_SetFont(&LCD_DEFAULT_FONT);
   
  /* dithering activation */
  LTDC_DitherCmd(ENABLE);
}

I'm using STemWIN and I noticed that also the GUIDRV_stm32f429i_discovery file as a similar part as above called during the GUI_Init function. I also changed the timing settings of this part to work as the same as the first file.
Thanks for your help!

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