STM32CubeExpansion_LRWAN : vcom.c -->> vcom_Init( )

Here is a suggestion: forget vcom.c altogether.

Write this function in your code.

/**
 * Write to the UART.
 *
 * Used by printf, puts and other similar functions in stdio. Writes
 * at the most ‘length’ bytes and returns the number of bytes written.
 *
 * @param handle the file handle (unused)
 * @param buff a buffer with the string to write
 * @param length the number of characters to write
 * @return the number of characters written
 */
int
_write(int handle, char *buff, int length) {
 (void)handle;
 
#ifdef DEBUG_WITH_UART
 HAL_UART_Transmit(&huart1, (uint8_t *)buff, length, TRANSMISSION_DELAY);
#endif // DEBUG_WITH_UART
 
 return 0;
}

Now you can use printf to format and send your code. If you do not define DEBUG_WITH_UART, the function will do nothing and will probably be optimised away.

To initialise the serial port, this is what I use:

/**
 * Configure and initialise UART1.
 *
 * UART1 is configured at 460800 bps, 8N1. DMA is not used, since it
 * was tested and interfered with the radio reception.
 */
void
serialPortConfig(void) {
 /* GPIO Ports Clock Enable */
 __HAL_RCC_GPIOA_CLK_ENABLE();
 
#if defined DEBUG_WITH_UART || !defined USE_STLINK_V2_1
 /* Peripheral clock enable */
 __HAL_RCC_USART1_CLK_ENABLE();
 
 huart1.Instance = USART1;
 huart1.Init.BaudRate = 460800;
 huart1.Init.WordLength = UART_WORDLENGTH_8B;
 huart1.Init.StopBits = UART_STOPBITS_1;
 huart1.Init.Parity = UART_PARITY_NONE;
 huart1.Init.Mode = UART_MODE_TX;
 huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
 huart1.Init.OverSampling = UART_OVERSAMPLING_16;
 huart1.Init.OneBitSampling = UART_ONEBIT_SAMPLING_DISABLED;
 huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
 
 HAL_UART_Init(&huart1);
 
 /* USART1 GPIO Configuration
 PA9 ------> USART1_TX
 PA10 ------> USART1_RX
 */
 GPIO_InitTypeDef GPIO_InitStruct = {0};
 
 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_VERY_HIGH;
 GPIO_InitStruct.Alternate = GPIO_AF4_USART1;
 
 HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
#endif // DEBUG_WITH_UART
}