ltdc驱动8位串行8位RGB

只看该作者 · 2016-3-15 17:16

我目前遇到一个LTDC的问题：
1.我这边有一个串行8bit的RGB显示屏，我将数据总线接在LTDC驱动器的B端口上,同时按照LCD规格书上设置了参数，但是实际显示的就是花屏。请问是否有人遇到同样问题？？？

只看该作者 · 2016-3-15 20:33

驱动程序是怎么写的呢？是不是上电顺序有问题

只看该作者 · 2016-3-16 08:54

你用的是那个开发板吗，上面带个小液晶屏的，那个例程里不是有用法嘛，按照那个随便改改就行了。

只看该作者 · 2016-3-16 08:57

为了方便以后快速查阅代码，提高开发效率，在这里特将LTDC驱动的初始化代码贴上来。本代码是基于ST官方STM32F429 Discovery Demo板的，学习LTDC驱动时参考了Demo板的官方例程，但是总觉得官方例程写得有点繁琐，不简洁明了，于是在此基础上重新整理代码得到如下初始化模板。

说明：本测试例程只使用了Layer1，显示缓冲区为FrameBuffer，颜色格式为RGB565，初始时缓冲区为0，所以显示Layer1时是全黑色，如果不使能Layer1只显示background，则屏幕显示为红色。

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void LCD_Init(void)

{

  LTDC_InitTypeDef               LTDC_InitStruct;

    

  /* Configure the LCD Control pins ------------------------------------------*/

  LCD_CtrlLinesConfig();

  

  /* Configure the LCD_SPI interface -----------------------------------------*/

  LCD_SPI_Config(); 

  

  /* Power on the LCD --------------------------------------------------------*/

  LCD_PowerOn();

  

  /* Enable the LTDC Clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_LTDC, ENABLE);

  

  /* Configure the LCD Control pins */

  LCD_GPIO_Config();  

    

  /* Enable Pixel Clock ------------------------------------------------------*/

  

  /* Configure PLLSAI prescalers for LCD */

  /* 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 = 192/3 = 64 Mhz */

  /* LTDC clock frequency = PLLLCDCLK / RCC_PLLSAIDivR = 64/8 = 8 Mhz */

  RCC_PLLSAIConfig(192, 7, 3);

  RCC_LTDCCLKDivConfig(RCC_PLLSAIDivR_Div8);

  

  /* Enable PLLSAI Clock */

  RCC_PLLSAICmd(ENABLE);

  /* Wait for PLLSAI activation */

  while(RCC_GetFlagStatus(RCC_FLAG_PLLSAIRDY) == RESET)

  {

  }

  

  /* LTDC Initialization -----------------------------------------------------*/

  

  /* 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;

  

  /* Timing configuration */

  /* Configure horizontal synchronization width */     

  //LTDC_InitStruct.LTDC_HorizontalSync = 9;

  LTDC_InitStruct.LTDC_HorizontalSync = 9;

  /* Configure vertical synchronization height */

  LTDC_InitStruct.LTDC_VerticalSync = 1;

  /* Configure accumulated horizontal back porch */

  LTDC_InitStruct.LTDC_AccumulatedHBP = 29; 

  /* Configure accumulated vertical back porch */

  LTDC_InitStruct.LTDC_AccumulatedVBP = 3;  

  /* Configure accumulated active width */  

  LTDC_InitStruct.LTDC_AccumulatedActiveW = 269;

  /* Configure accumulated active height */

  LTDC_InitStruct.LTDC_AccumulatedActiveH = 323;

  /* Configure total width */

  LTDC_InitStruct.LTDC_TotalWidth = 279; 

  /* Configure total height */

  LTDC_InitStruct.LTDC_TotalHeigh = 327;

    

  /* Configure R,G,B component values for LCD background color */                   

  LTDC_InitStruct.LTDC_BackgroundRedValue = 0xff;            

  LTDC_InitStruct.LTDC_BackgroundGreenValue = 0;          

  LTDC_InitStruct.LTDC_BackgroundBlueValue = 0; 

  

  LTDC_Init(<DC_InitStruct);

}

LCD串行控制信号线配置：

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void LCD_CtrlLinesConfig(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;



  /* Enable GPIOs clock*/

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOD, ENABLE);



  /* Configure NCS in Output Push-Pull mode */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;

  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(GPIOC, &GPIO_InitStructure);

  

  /* Configure WRX in Output Push-Pull mode */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;

  GPIO_Init(GPIOD, &GPIO_InitStructure);



  /* Set chip select pin high */

  GPIO_SetBits(GPIOC, GPIO_Pin_2); 

}

[code]void LCD_SPI_Config(void)
{
  SPI_InitTypeDef SPI_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;

  /* Enable LCD_SPI_SCK_GPIO_CLK, LCD_SPI_MISO_GPIO_CLK and LCD_SPI_MOSI_GPIO_CLK clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE);

  /* Enable LCD_SPI and SYSCFG clock  */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI5, ENABLE);

  /* Configure LCD_SPI SCK pin */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
  GPIO_Init(GPIOF, &GPIO_InitStructure);

  /* Configure LCD_SPI MISO pin */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
  GPIO_Init(GPIOF, &GPIO_InitStructure);

  /* Configure LCD_SPI MOSI pin */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_Init(GPIOF, &GPIO_InitStructure);

  /* Connect SPI SCK */
  GPIO_PinAFConfig(GPIOF, GPIO_PinSource7, GPIO_AF_SPI5);

  /* Connect SPI MISO */
  GPIO_PinAFConfig(GPIOF, GPIO_PinSource8, GPIO_AF_SPI5);

  /* Connect SPI MOSI */
  GPIO_PinAFConfig(GPIOF, GPIO_PinSource9, GPIO_AF_SPI5);

  SPI_I2S_DeInit(SPI5);

  /* SPI configuration -------------------------------------------------------*/
  SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
  SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
  SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
  SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
  SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
  /* SPI baudrate is set to 5.6 MHz (PCLK2/SPI_BaudRatePrescaler = 90/16 = 5.625 MHz)

只看该作者 · 2016-3-16 08:58

LCD上电初始化序列，请对照LCD datasheet要求进行配置，此处省略部分内容：
/**
  * @brief  Configure the LCD controller (Power On sequence as described in ILI9341 Datasheet)
  * @param  None
  * @retval None
  */
void LCD_PowerOn(void)
{
  LCD_WriteCommand(0xCA);
  LCD_WriteData(0xC3);
  LCD_WriteData(0x08);
  LCD_WriteData(0x50);
  LCD_WriteCommand(LCD_POWERB);
  LCD_WriteData(0x00);
  LCD_WriteData(0xC1);
  LCD_WriteData(0x30);
  LCD_WriteCommand(LCD_POWER_SEQ);
  LCD_WriteData(0x64);
  LCD_WriteData(0x03);
  LCD_WriteData(0x12);
  LCD_WriteData(0x81);

  ...

  LCD_WriteCommand(LCD_SLEEP_OUT);
  delay(200);
  LCD_WriteCommand(LCD_DISPLAY_ON);
  /* GRAM start writing */
  LCD_WriteCommand(LCD_GRAM);
}
Layer初始化：

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void LCD_Layer1Init(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 + 240 -1

  Vertical start   = vertical synchronization + vertical back porch     = 4

  Vertical stop   = Vertical start + window height -1  = 4 + 160 -1      */ 

  LTDC_Layer_InitStruct.LTDC_HorizontalStart = 30;

  LTDC_Layer_InitStruct.LTDC_HorizontalStop = (240 + 30 - 1); 

  LTDC_Layer_InitStruct.LTDC_VerticalStart = 4;

  LTDC_Layer_InitStruct.LTDC_VerticalStop = 320 + 4 -1; 

  

  /* Pixel Format configuration*/           

  LTDC_Layer_InitStruct.LTDC_PixelFormat = LTDC_Pixelformat_RGB565;

  

  /* Alpha constant (255 totally opaque) */

  LTDC_Layer_InitStruct.LTDC_ConstantAlpha = 255; 

  

  /* Configure blending factors */       

  LTDC_Layer_InitStruct.LTDC_BlendingFactor_1 = LTDC_BlendingFactor1_PAxCA;    

  LTDC_Layer_InitStruct.LTDC_BlendingFactor_2 = LTDC_BlendingFactor2_PAxCA;  

  

  /* 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;   

  

  /* Input Address configuration */    

  LTDC_Layer_InitStruct.LTDC_CFBStartAdress = (u32)FrameBuffer;

  

  /* 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         = 240 

  number of bytes per pixel = 2    (pixel_format : RGB565) 

  */

  LTDC_Layer_InitStruct.LTDC_CFBLineLength = ((240 * 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 = (240 * 2);  

  

  /* configure the number of lines */

  LTDC_Layer_InitStruct.LTDC_CFBLineNumber = 320;

  

  LTDC_LayerInit(LTDC_Layer1, <DC_Layer_InitStruct);

  LTDC_LayerCmd(LTDC_Layer1, ENABLE);

  LTDC_ReloadConfig(ENABLE);

}

主程序：

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int main(void)

{

  LCD_Init();

  LCD_Layer1Init();

  LTDC_Cmd(ENABLE);



  while(1);

}

只看该作者 · 2016-3-16 10:19

你们上面所提到的都是并行的RGB通信方式，这个没有问题是可以的，目前我们用的是串行RGB的方式，不知道这个怎么弄？