STM32H747 MIPI DSI intreface problem (no signal on DSI data lines in LP command mode)

[AlexVetoshko]

Hello!

I have problem with initialization MIPI DSI interface on STM32H747. I use this interface for connect round LCD display with the St7797 display controller. But the problem is that when sending a sequence of LP commands to initialize the display, there is no data on the D0P and D0N lines. In this case, the signal is constantly present on the CLK lines.

I am attaching a test project with settings. Tell me where the problem might be?

UPDATE: If use LTDC controller, video data present on data line.

But there is nothing on the data lines when sending init commands to display.

I am attaching a test CubeIDE project with interface initialization.

Regards, Alex

[Ons KOOLI]

Hi @AlexVetoshko​ ,

Please refer to the STM32CubeH7 LCD_DSI example under the following location: Projects\STM32H747I-DISCO\Examples

Best Regards,

Ons.

[AlexVetoshko]

Hello!

Yes, I looked at this example. In this example, commands are transmitted normally. But there the DSI module is used in a different mode (Adaptive Command Mode). My display requires video mode. And in this mode, I cannot send LP commands for initialization (I do not see any signals on the data line). Because of this, I can not initialize the display controller. In this case, the video data (when the LTDС module is turned on) is normal. What is the problem?

Can you help me?

I am attaching the code with the initialization of the DSI module:

static void MX_DSIHOST_DSI_Init(void)

{

 DSI_PLLInitTypeDef PLLInit = {0};

 DSI_HOST_TimeoutTypeDef HostTimeouts = {0};

 DSI_PHY_TimerTypeDef PhyTimings = {0};

 DSI_VidCfgTypeDef VidCfg = {0};

 /* USER CODE BEGIN DSIHOST_Init 1 */

 /* USER CODE END DSIHOST_Init 1 */

 hdsi.Instance = DSI;

 hdsi.Init.AutomaticClockLaneControl = DSI_AUTO_CLK_LANE_CTRL_ENABLE;

 hdsi.Init.TXEscapeCkdiv = 2;

 hdsi.Init.NumberOfLanes = DSI_ONE_DATA_LANE;

 PLLInit.PLLNDIV = 10;

 PLLInit.PLLIDF = DSI_PLL_IN_DIV1;

 PLLInit.PLLODF = DSI_PLL_OUT_DIV1;

 if (HAL_DSI_Init(&hdsi, &PLLInit) != HAL_OK)

 {

   Error_Handler();

 }

 HostTimeouts.TimeoutCkdiv = 1;

 HostTimeouts.HighSpeedTransmissionTimeout = 0;

 HostTimeouts.LowPowerReceptionTimeout = 0;

 HostTimeouts.HighSpeedReadTimeout = 0;

 HostTimeouts.LowPowerReadTimeout = 0;

 HostTimeouts.HighSpeedWriteTimeout = 0;

 HostTimeouts.HighSpeedWritePrespMode = DSI_HS_PM_DISABLE;

 HostTimeouts.LowPowerWriteTimeout = 0;

 HostTimeouts.BTATimeout = 0;

 if (HAL_DSI_ConfigHostTimeouts(&hdsi, &HostTimeouts) != HAL_OK)

 {

   Error_Handler();

 }

 PhyTimings.ClockLaneHS2LPTime = 20;

 PhyTimings.ClockLaneLP2HSTime = 18;

 PhyTimings.DataLaneHS2LPTime = 10;

 PhyTimings.DataLaneLP2HSTime = 13;

 PhyTimings.DataLaneMaxReadTime = 0;

 PhyTimings.StopWaitTime = 0;

 if (HAL_DSI_ConfigPhyTimer(&hdsi, &PhyTimings) != HAL_OK)

 {

   Error_Handler();

 }

 if (HAL_DSI_ConfigFlowControl(&hdsi, DSI_FLOW_CONTROL_BTA) != HAL_OK)

 {

   Error_Handler();

 }

 if (HAL_DSI_SetLowPowerRXFilter(&hdsi, 10000) != HAL_OK)

 {

   Error_Handler();

 }

 if (HAL_DSI_ConfigErrorMonitor(&hdsi, HAL_DSI_ERROR_NONE) != HAL_OK) // HAL_DSI_ERROR_NONE

 {

   Error_Handler();

 }

 LPCmd.LPGenShortWriteNoP = DSI_LP_GSW0P_ENABLE;

 LPCmd.LPGenShortWriteOneP = DSI_LP_GSW1P_ENABLE;

 LPCmd.LPGenShortWriteTwoP = DSI_LP_GSW2P_ENABLE;

 LPCmd.LPGenShortReadNoP = DSI_LP_GSR0P_ENABLE;

 LPCmd.LPGenShortReadOneP = DSI_LP_GSR1P_ENABLE;

 LPCmd.LPGenShortReadTwoP = DSI_LP_GSR2P_ENABLE;

 LPCmd.LPGenLongWrite = DSI_LP_GLW_ENABLE;

 LPCmd.LPDcsShortWriteNoP = DSI_LP_DSW0P_ENABLE;

 LPCmd.LPDcsShortWriteOneP = DSI_LP_DSW1P_ENABLE;

 LPCmd.LPDcsShortReadNoP = DSI_LP_DSR0P_ENABLE;

 LPCmd.LPDcsLongWrite = DSI_LP_DLW_ENABLE;

 LPCmd.LPMaxReadPacket = DSI_LP_MRDP_ENABLE;

 LPCmd.AcknowledgeRequest = DSI_ACKNOWLEDGE_ENABLE;

 if (HAL_DSI_ConfigCommand(&hdsi, &LPCmd) != HAL_OK)

 {

   Error_Handler();

 }

 /*Video Mode initialization*/

 VidCfg.VirtualChannelID = 0;

 /*DSI Host Color format configuration. The image data is transmitted using Packed Pixel Stream with 24 bit format.*/

 VidCfg.ColorCoding = DSI_RGB888;

 VidCfg.LooselyPacked = DSI_LOOSELY_PACKED_DISABLE;

 /*Video mode configuration*/

 VidCfg.Mode = DSI_VID_MODE_BURST;

 /*Video packet configuration*/

 VidCfg.PacketSize = 400;

 VidCfg.NumberOfChunks = 0;

 VidCfg.NullPacketSize = 0;

 /*Signal polarity configuration. Same polarity between LTDC and DSI except for Data Enable which has opposite polarity */

 VidCfg.HSPolarity = DSI_HSYNC_ACTIVE_LOW;//correct

 VidCfg.VSPolarity = DSI_VSYNC_ACTIVE_LOW;//correct

 VidCfg.DEPolarity = DSI_DATA_ENABLE_ACTIVE_HIGH;//correct

 /*Video timing configuration. Retrieved from LTDC config*/

 VidCfg.HorizontalSyncActive = HSYNC * LBCLK_PCLK_MULT; //lane byte clock cycles

 VidCfg.HorizontalBackPorch = HBP * LBCLK_PCLK_MULT; //lane byte clock cycles

 VidCfg.HorizontalLine = (HSYNC + HBP + HACT + HFP) * LBCLK_PCLK_MULT; //lane byte clock cycles

 VidCfg.VerticalSyncActive = VSYNC;

 VidCfg.VerticalBackPorch = VBP;

 VidCfg.VerticalFrontPorch = VFP;

 VidCfg.VerticalActive = VACT;

 /*Command transmission mode and Max LP packet size*/

 VidCfg.LPCommandEnable = DSI_LP_COMMAND_ENABLE;

 VidCfg.LPLargestPacketSize = 29;

 VidCfg.LPVACTLargestPacketSize = 8;

 /*LP transition configuration. It is recommended to enable LP transition in all regions*/

 VidCfg.LPHorizontalFrontPorchEnable = DSI_LP_HFP_ENABLE;

 VidCfg.LPHorizontalBackPorchEnable = DSI_LP_HBP_ENABLE;

 VidCfg.LPVerticalActiveEnable = DSI_LP_VACT_ENABLE;

 VidCfg.LPVerticalFrontPorchEnable = DSI_LP_VFP_ENABLE;

 VidCfg.LPVerticalBackPorchEnable = DSI_LP_VBP_ENABLE;

 VidCfg.LPVerticalSyncActiveEnable = DSI_LP_VSYNC_ENABLE;/*Flow control configuration*/

 VidCfg.FrameBTAAcknowledgeEnable = DSI_FBTAA_ENABLE;//needed for commands in video mode

 if (HAL_DSI_ConfigVideoMode(&hdsi, &VidCfg) != HAL_OK)

 {

   Error_Handler();

 }

 if (HAL_DSI_SetGenericVCID(&hdsi, 0) != HAL_OK)

 {

   Error_Handler();

 }

 __HAL_LTDC_DISABLE(&hltdc);

 HAL_DSI_Start(&(hdsi));

 LOG_INFO("Start display init\r\n");

 LCD_Reset();

 HAL_Delay(120);

 St7797_Init_sequence();

      LOG_INFO("Disable command mode \r\n");

      LPCmd.LPGenShortWriteNoP = DSI_LP_GSW0P_DISABLE;

      LPCmd.LPGenShortWriteOneP = DSI_LP_GSW1P_DISABLE;

      LPCmd.LPGenShortWriteTwoP = DSI_LP_GSW2P_DISABLE;

      LPCmd.LPGenShortReadNoP = DSI_LP_GSR0P_DISABLE;

      LPCmd.LPGenShortReadOneP = DSI_LP_GSR1P_DISABLE;

      LPCmd.LPGenShortReadTwoP = DSI_LP_GSR2P_DISABLE;

      LPCmd.LPGenLongWrite = DSI_LP_GLW_DISABLE;

      LPCmd.LPDcsShortWriteNoP = DSI_LP_DSW0P_DISABLE;

      LPCmd.LPDcsShortWriteOneP = DSI_LP_DSW1P_DISABLE;

      LPCmd.LPDcsShortReadNoP = DSI_LP_DSR0P_DISABLE;

      LPCmd.LPDcsLongWrite = DSI_LP_DLW_DISABLE;

      LPCmd.LPMaxReadPacket = DSI_LP_MRDP_DISABLE;

      LPCmd.AcknowledgeRequest = DSI_ACKNOWLEDGE_DISABLE;

      if (HAL_DSI_ConfigCommand(&hdsi, &LPCmd) != HAL_OK)

      {

          Error_Handler();

      }

 /* USER CODE BEGIN DSIHOST_Init 2 */

 /* USER CODE END DSIHOST_Init 2 */

}

[wrfrf.1]

Hi Ons KOOLI (ST Employee)

Can you help us?

We really need to know, it's very critical on this moment for us. 

[Ons KOOLI]

Hi @wrfrf.1​ ,

I am rising your claim internally to get help from specific dev team.

Best Regards,

Ons.

[Ons KOOLI]

Hi @wrfrf.1​ ,

As recommended by our dev team, can you disable the AutomaticClockLaneControl:

hdsi.Init.AutomaticClockLaneControl = DSI_AUTO_CLK_LANE_CTRL_DISABLE;

and inform me if this fixes the problem.

Best Regards,

Ons.

[AlexVetoshko]

Hi Ons KOOLI ! We have checked your recommendation and changed this parameter. However, this did not solve the problem - there are no signals on the data lines in the command mode.

[nwm_35]

Alex,

Did you ever figure this out? I'm in a very similar situation with an stm32u5a9 driving a ILI9881C. I'm trying to send low power commands to set up the controller but my controller only supports video mode and I'm seeing no signal on the DSI lines.