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AlexCaron
Explorer
November 7, 2024
Solved

STM32H7S, LTCD and uart won't work together

  • November 7, 2024
  • 1 reply
  • 2441 views

Hi, 

I'm using a STM32H7S78-DK board along with stm32cudeide 1.16.0. I'm loading the example LTDC_ColorKeyring which work fine, here is the issue... I'm trying to implement uart4 connected to the onboard ST-link. If I init MX_UART4_Init() and use HAL_UART_Transmit(), BEFORE MX_LTDC_Init(), it work fine. As soon as the LTDC is init, I cannot use the Uart at all. I don't see any pin conflict here... the uart4_tx is PD1 and is only connect to the VCP of the st-link.

I'm evaluating the STM32H7S for business, but if I cannot get those two simple peripheral working together...thats a big flaw

    This topic has been closed for replies.
    Best answer by STM_Thirty2

    In the code below from HAL_LTDC_MspInit we can see that in the USER CODE BEGIN section we make a new RCC_OscInitTypeDef with a vlaue of zero , this clears out any values from our original RCC settings , in this case

    HSI calibration value. In the code below it is never initialized  again, when the struct is passed to HAL_RCC_OscConfig(&RCC_OscInitStruct) (line 153)  sets HSI calibration value to 0 since it was never initialized in this struct. 

     

    The solution is to add RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT before the call to HAL_RCC_OscConfig (line 152 below)

     

    Admittedly the example has a few issues, for example the .ioc file sets LTDC to 200MHZ, but fixing it and regenerating does not generate a SystemClockConfig function, hence why the clock is configured in user space. 

     

    For now the solution provided fixes the original post's issue. The bugs have been reported internally.

     

     

     

     

    void HAL_LTDC_MspInit(LTDC_HandleTypeDef* hltdc)
{
 GPIO_InitTypeDef GPIO_InitStruct = {0};
 RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
 if(hltdc->Instance==LTDC)
 {
 /* USER CODE BEGIN LTDC_MspInit 0 */
 RCC_OscInitTypeDef RCC_OscInitStruct={0};
 /* USER CODE END LTDC_MspInit 0 */

 /** Initializes the peripherals clock
 */
 PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LTDC;
 PeriphClkInit.LtdcClockSelection = RCC_LTDCCLKSOURCE_PLL3R;
 if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
 {
 Error_Handler();
 }

 /* Peripheral clock enable */
 __HAL_RCC_LTDC_CLK_ENABLE();

 __HAL_RCC_GPIOD_CLK_ENABLE();
 __HAL_RCC_GPIOB_CLK_ENABLE();
 __HAL_RCC_GPIOG_CLK_ENABLE();
 __HAL_RCC_GPIOE_CLK_ENABLE();
 __HAL_RCC_GPIOA_CLK_ENABLE();
 __HAL_RCC_GPIOF_CLK_ENABLE();
 /**LTDC GPIO Configuration
 PD3 ------> LTDC_B1
 PB5 ------> LTDC_R2
 PG0 ------> LTDC_R7
 PB3(JTDO/TRACESWO) ------> LTDC_R4
 PG2 ------> LTDC_HSYNC
 PE11 ------> LTDC_VSYNC
 PA12 ------> LTDC_B2
 PA11 ------> LTDC_B3
 PB4(NJTRST) ------> LTDC_R3
 PA9 ------> LTDC_B5
 PG1 ------> LTDC_R6
 PA10 ------> LTDC_B4
 PG12 ------> LTDC_G1
 PA8 ------> LTDC_B6
 PG13 ------> LTDC_CLK
 PA15(JTDI) ------> LTDC_R5
 PF7 ------> LTDC_G0
 PF9 ------> LTDC_R0
 PF10 ------> LTDC_R1
 PB12 ------> LTDC_G5
 PA0 ------> LTDC_G3
 PA1 ------> LTDC_G2
 PF11 ------> LTDC_B0
 PB14 ------> LTDC_DE
 PB15 ------> LTDC_G7
 PB11 ------> LTDC_G6
 PB13 ------> LTDC_G4
 PA6 ------> LTDC_B7
 */
 GPIO_InitStruct.Pin = GPIO_PIN_3;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
 HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_15|GPIO_PIN_13;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF10_LTDC;
 HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_2|GPIO_PIN_1|GPIO_PIN_12
 |GPIO_PIN_13;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF13_LTDC;
 HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_12|GPIO_PIN_14
 |GPIO_PIN_11;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF13_LTDC;
 HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_11;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF11_LTDC;
 HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_12|GPIO_PIN_11|GPIO_PIN_8|GPIO_PIN_15
 |GPIO_PIN_0|GPIO_PIN_1;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF13_LTDC;
 HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
 HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_7|GPIO_PIN_9;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF13_LTDC;
 HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_10|GPIO_PIN_11;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
 HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);

 GPIO_InitStruct.Pin = GPIO_PIN_6;
 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 GPIO_InitStruct.Alternate = GPIO_AF12_LTDC;
 HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

 /* USER CODE BEGIN LTDC_MspInit 1 */
 /* LCD clock configuration */
 /* Typical PCLK is 25 MHz so the PLL3R is configured to provide this clock */
 /* LCD clock configuration */

 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
 RCC_OscInitStruct.HSIState = RCC_HSI_ON;
 RCC_OscInitStruct.PLL1.PLLState = RCC_PLL_NONE;
 RCC_OscInitStruct.PLL2.PLLState = RCC_PLL_NONE;
 RCC_OscInitStruct.PLL3.PLLState = RCC_PLL_ON;
 RCC_OscInitStruct.PLL3.PLLSource = RCC_PLLSOURCE_HSI;

 RCC_OscInitStruct.PLL3.PLLM = 4;
 RCC_OscInitStruct.PLL3.PLLN = 25;
 RCC_OscInitStruct.PLL3.PLLP = 2;
 RCC_OscInitStruct.PLL3.PLLQ = 20;
 RCC_OscInitStruct.PLL3.PLLR = 16;
 RCC_OscInitStruct.PLL3.PLLS = 2;
 RCC_OscInitStruct.PLL3.PLLT = 2;
 RCC_OscInitStruct.PLL3.PLLFractional = 0;
 RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
 if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
 {
 /* Initialization error */
 while(1);
 }
 PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LTDC;
 PeriphClkInit.LtdcClockSelection = RCC_LTDCCLKSOURCE_PLL3R;

 if(HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
 {
 while(1);
 }
 /* USER CODE END LTDC_MspInit 1 */

 }

}

     

     

     

     

    1 reply

    I
    Imen.D
    Technical Moderator
    November 7, 2024

    Hello @AlexCaron ,

    Let me first welcome you to the ST Community.

    Please check the clock configuration is initialized/enabled properly for both peripherals. 

    Did you follow exactly the readme? Also, check the hardware connections.

    A
    AlexCaronAuthor
    Explorer
    November 7, 2024

    Hi Imen,

    Thank you for your reply, as I said, they both work unless the ltdc is started so I assume both clock/configuration are fine. Starting the ltdc completely stop the uart4 to work. Anyway the project is comming from one of your example, maybe you should check ?

    I
    Imen.D
    Technical Moderator
    November 7, 2024

    As a first check, we noticed that there are differences between the pinout for the display connector of the LTDC_ColorKeying example and the pinout of the schematic:

    The issue is on LTDC_R2 which was connected to pin PB5 in the SW-example, but it was connected to PF0 on the schematic.

    Please, check your LTDC pin configuration, as it can be the same issue for you and in this case the board doesn't work.

    This issue is escalated internally for fix in the coming release of software.

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