uart8 get only get noise in stm32h747i-disco

[wjian.2]

if in the osciloscopio only get noise in the HAL_UART_Transmit(&huart8,(uint8_t*)msg,strlen(msg),100); which part of code should be bad

static void MX_GPIO_Init(void)

{

 GPIO_InitTypeDef GPIO_InitStruct;

 /* GPIO Ports Clock Enable */

 __HAL_RCC_GPIOJ_CLK_ENABLE();

 __HAL_RCC_UART8_CLK_ENABLE();

 /*Configure GPIO pin: PJ8   For D1 pin for TX */

 GPIO_InitStruct.Pin = GPIO_PIN_8;

// GPIO_InitStruct.Pin = GPIO_PIN_8 | GPIO_PIN_9;

 //GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;

 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;

 //GPIO_InitStruct.Pull = GPIO_NOPULL; //pullup

 GPIO_InitStruct.Pull = GPIO_PULLUP; //pullup

 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

 GPIO_InitStruct.Alternate = GPIO_AF8_UART8;

  HAL_GPIO_Init(GPIOJ, &GPIO_InitStruct);

 /*Configure GPIO pin: PJ9   For D0 pin for RX */

 GPIO_InitStruct.Pin = GPIO_PIN_9;

 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; //MODE_ALTERNATE?

 //GPIO_InitStruct.Pull = GPIO_NOPULL; //or NOPULL?

 GPIO_InitStruct.Pull = GPIO_PULLUP;

 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

 GPIO_InitStruct.Alternate = GPIO_AF8_UART8;

HAL_GPIO_Init(GPIOJ, &GPIO_InitStruct);

}

static void MX_UART8_Init(void)
{
__HAL_RCC_UART8_CLK_ENABLE();

//__HAL_UART_CLEAR_IDLEFLAG(&huart8);
/* USER CODE BEGIN USART1_Init 0 */

/* USER CODE END USART1_Init 0 */

/* USER CODE BEGIN USART1_Init 1 */

/* USER CODE END USART1_Init 1 */
huart8.Instance = UART8;
huart8.Init.BaudRate = 9600;
huart8.Init.WordLength = UART_WORDLENGTH_8B;
huart8.Init.StopBits = UART_STOPBITS_1;
huart8.Init.Parity = UART_PARITY_NONE;
huart8.Init.Mode = UART_MODE_TX_RX;
huart8.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart8.Init.OverSampling = UART_OVERSAMPLING_16;
huart8.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart8.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart8.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;

if (HAL_UART_Init(&huart8) != HAL_OK)
{
Error_Handler();
}

}

[Tesla DeLorean]

Doesn't show how the code is called, or what the signal looks like.

Probes properly grounded?

Perhaps configure PJ8 as a GPIO and drive that high/low in a manner you can review / inspect ?

Should be the only connection for PJ8, not really understanding how it go this complicated / difficult.

Are there different versions of the H747I-DISCO board? What version are you using?

[Tesla DeLorean]

Watch that msg has usable content. Perhaps send "UUUUU" strings?

[wjian.2]

" how the code is called"

 not this HAL_UART_Transmit(&huart8,(uint8_t*)msg,strlen(msg),100)? en usart1 (same configution but with no pin use usb)is "beer 50 % cake 50 % etc"  

run as 0V.

"high/low in a manner you can review / inspect" this mean writepin?

DK32H7H747I$AT2

[Tesla DeLorean]

What version of the MB1248 board?

The static state of the UART TX pin should be HIGH

I mean HAL_GPIO_WritePin() or interaction with GPIOJ->ODR and readback via GPIOJ->IDR

Check the settings in RCC, GPIO and UART8 peripherals, inspect the registers.

Anything running in the M4 core that might interfere with what the M7 core is doing?

You're checking the right pins? The code is running and not crashing or faulting?

[wjian.2]

MB1248-D03

After HAL_GPIO_Init(GPIOJ, &GPIO_InitStruct); I think should not add  HAL_GPIO_WritePin(GPIOJ，GPIO_PIN_8，1) ？

In my debug gpioj run as

In my register D0/D1 as（i dont know its same thing o no）

which part of rcc should i check

uart 8

[Tesla DeLorean · Accepted solution]

This is generating UART8 output on Pin D1 (PJ8), also blink LED1 to show it's alive and running. Should see roughly 4.8 KHz square wave

Use the .HEX, the .c file reflect's the project's primary main.c file

[wjian.2]

Thanks a lot i have find my problem

[Tesla DeLorean]

What did the problem turn out to be? Might help others in similar situations