USART4 issue on Nucleo-G071RB

[fpistm]

Hello @fpistm , I was further exploring more uart for my project and found that UART4 on pin PA1 & PA0 also do not work under Arduino framework.

I have tested the UART1, UART2 & UART4 using STM32Cube Framework and everything works fine.

#include <Arduino.h> 

#define pin  LED_BUILTIN

HardwareSerial UART1(PA10, PA9);          // works fine after workaround provided by @fpistm in above comments
HardwareSerial Uart4(PA1, PA0);             // UART 4 on Pin PA1 & PA0 does not work and MCU stop working.
UART_HandleTypeDef huart4;                 // HACK using STM32 HAL Library  for UART4 on Pin PA1 & PA0

void Uart4_Init();
void UART4_Send(); 
 
void setup()
{
  Serial.begin(115200);               // on Pin rx_PA3 tx_PA2
  delay(100);

  UART1.begin(115200);             // on Pin rx_PA10 tx_PA9 
  delay(100);

  Uart4.begin(115200);               // Error working using Arduino library // on Pin rx_PA1 tx_PA0
  //Uart4_Init();                           // using STM32 HAL Library as workaround to send data but cannot receive due to lib conflict
  delay(100);

  pinMode(LED_BUILTIN, OUTPUT);
  
}

int count = 0;
void loop()
{
  delay(1000); 

  Serial.print("\nSG0  UART2(Serial): "); Serial.print(++count);
  
  UART1.print("\nSG0 UART1: "); UART1.print(count);
  
  Uart4.print("\nSG0 Uart4: "); Uart4.print(count); // **SOC stop working at this point...**
  
  //UART4_Send(); //using STM32 HAL Library (Sending is fine, receiving data is problem)
 
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
}

/* Sending data on UART 4 using STM32 HAL Library*/
void UART4_Send()
{
   char str[20];
   String thisString = "\nSG0  UART4: " + String(count) + "\n";
   thisString.toCharArray(str, thisString.length());
   HAL_UART_Transmit(&huart4, (uint8_t*)str, thisString.length()-1, 1000);
}

/* Initializing UART 4 using STM32 HAL Library*/ 
void Uart4_Init()
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  /* Peripheral clock enable */
  __HAL_RCC_USART4_CLK_ENABLE();

  __HAL_RCC_GPIOA_CLK_ENABLE();
  /**USART4 GPIO Configuration
  PA0     ------> USART4_TX
  PA1     ------> USART4_RX
  */
  GPIO_InitStruct.Pin = 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_AF4_USART4;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

     /* USER CODE END USART4_Init 1 */
  huart4.Instance = USART4;
  huart4.Init.BaudRate = 115200;
  huart4.Init.WordLength = UART_WORDLENGTH_8B;
  huart4.Init.StopBits = UART_STOPBITS_1;
  huart4.Init.Parity = UART_PARITY_NONE;
  huart4.Init.Mode = UART_MODE_TX_RX;
  huart4.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart4.Init.OverSampling = UART_OVERSAMPLING_16;
  huart4.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart4.Init.ClockPrescaler = UART_PRESCALER_DIV1;
  huart4.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;

  if (HAL_UART_Init(&huart4) != HAL_OK)
  { 
    Serial.println("\nUart4 Error");
  }
  /* USER CODE BEGIN USART4_Init 2 */
  
  if (HAL_UARTEx_SetTxFifoThreshold(&huart4, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Serial.println("\nUart4 Error");
  }

  if (HAL_UARTEx_SetRxFifoThreshold(&huart4, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Serial.println("\nUart4 Error");
  }

  if (HAL_UARTEx_DisableFifoMode(&huart4) != HAL_OK)
  {
    Serial.println("\nUart4 Error");
  } 
}

Originally posted by @harji2130 in #1180 (comment)