UART printing gibbersh to TeraTerm

[NicRoberts]

NUCLEO F767ZI, CubeIDE 2.1.1, CubeMX 6.17.0

I'm trying to set up UART with printf()

#include <stdio.h>

UART_HandleTypeDef huart3;
static void MX_USART3_UART_Init(void);

int __io_putchar(int ch)
{
    HAL_UART_Transmit(&huart3, (uint8_t *)ch, 1, 10);
    return ch;
}

....
// in main
// in while
prinf("UART test\r\n");

// MX generated USART3 init
static void MX_USART3_UART_Init(void)
{

  /* USER CODE BEGIN USART3_Init 0 */

  /* USER CODE END USART3_Init 0 */

  /* USER CODE BEGIN USART3_Init 1 */

  /* USER CODE END USART3_Init 1 */
  huart3.Instance = USART3;
  huart3.Init.BaudRate = 115200;
  huart3.Init.WordLength = UART_WORDLENGTH_8B;
  huart3.Init.StopBits = UART_STOPBITS_1;
  huart3.Init.Parity = UART_PARITY_NONE;
  huart3.Init.Mode = UART_MODE_TX_RX;
  huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart3.Init.OverSampling = UART_OVERSAMPLING_16;
  huart3.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart3.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart3) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART3_Init 2 */

  /* USER CODE END USART3_Init 2 */

}

Clock tree from MX

Output in Tera Term window

TT is set up exactly the same as the UART init in the code.

Anyone know whats going on here?

[mƎALLEm]

Hello,

You have set a wrong HSE clock value to 25MHz:

You need to set it to 8MHz as the ST-LINK-V2 MCO output on that Nucleo board is 8MHz

[Andrew Neil]

Gibberish on a terminal is almost always due to wrong baud rate.

As @mƎALLEm said, if you enter the wrong value for the HSE clock frequency, then your baud rate will be wrong - as will any other frequencies derived from HSE.

[NicRoberts]

Still gibberish

[mƎALLEm]

Did you regenerate the code, compile it with that config and upload the application to the MCU?

[NicRoberts]

Yes

[mƎALLEm]

And what if you select HSI as clock source instead of HSE?:

If it's working, that means definetly you have an issue with HSE, a missing solder bridge on STLINK MCO output path or something similar. If not, you have an issue with TeraTerm UART configuration.

[NicRoberts]

No not working with HSI either

Settings in TT are the same as in the USART3 init. (I've also tried RealTerm & get the same gibberish there too)

[mƎALLEm]

Configure the data lenght in Tera term to 7 bit instead of 8 bit.

This is the example from CubeF7 https://github.com/STMicroelectronics/STM32CubeF7/blob/master/Projects/STM32F767ZI-Nucleo/Examples/UART/UART_Printf/

that suggests in its readme file that you need to set the datalenght to 7 bit:

This is what was said in a comment the example code: Word Length = 8 Bits (7 data bit + 1 parity bit)

 /* UART configured as follows:
      - Word Length = 8 Bits (7 data bit + 1 parity bit) : 
	                  BE CAREFUL : Program 7 data bits + 1 parity bit in PC HyperTerminal
      - Stop Bit    = One Stop bit
      - Parity      = ODD parity
      - BaudRate    = 9600 baud
      - Hardware flow control disabled (RTS and CTS signals) */
  UartHandle.Instance        = USARTx;

  UartHandle.Init.BaudRate   = 9600;
  UartHandle.Init.WordLength = UART_WORDLENGTH_8B;
  UartHandle.Init.StopBits   = UART_STOPBITS_1;
  UartHandle.Init.Parity     = UART_PARITY_ODD;
  UartHandle.Init.HwFlowCtl  = UART_HWCONTROL_NONE;
  UartHandle.Init.Mode       = UART_MODE_TX_RX;
  UartHandle.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&UartHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }

 This is apart of the wrong HSE frequency value you set in CubeMx: 25MHz instead of 8MHz (the issue I raised in a previous post).

Hope that helps

[NicRoberts]

Sorry but this doesn't solve the issue either.

Even reconfiguring the UART with an odd partity bit & changing the corresponding settings in TT as suggested, I'm still getting gibberish.