How forward data from COM PORT to UART

[arduo]

I want to forward all data received at the VCP with USB FS to UART how can i implement this specific in code?

I have been searching for long time for this and i have not found any good example of it.

Can you please help me?

Until now i am doing this like this in my main:

 uint8_t byte[1111];
	for (;;)
	{		
		if (VCP_read(&byte, 1) != 1)
			continue;
		
		HAL_UART_Transmit(&huart5, byte, sizeof(byte), HAL_MAX_DELAY);
		
		VCP_write("\r\nYou typed ", 12);
		VCP_write(&byte, 1);
		VCP_write("\r\n", 2);
	
	}
	

If you can help me i will reward you.

Thanks.

[S.Ma]

Only thing I can suggest is to look at cube SW source code, discovery

readme file:
 
/**
 @page CDC_Standalone USB Device Communication (CDC) application
 
 @verbatim
 ******************************************************************************
 * @file USB_Device/CDC_Standalone/readme.txt 
 * @author MCD Application Team
 * @brief Description of the USB Device CDC application.
 ******************************************************************************
 *
 * Copyright (c) 2017 STMicroelectronics International N.V. All rights reserved.
 *
 (...) too big for posting
 
@par Application Description 
 
This example describes how to use USB device application based on the Device 
Communication Class (CDC) following the PSTN subprotocol on the STM32L4xx devices.
 
This example is part of the USB Device Library package using STM32Cube firmware.
 
This is a typical application on how to use the STM32L496xx USB OTG Device peripheral where the STM32 MCU
behaves as a USB-to-UART bridge following the Virtual COM Port (VCP) implementation.
 - On one side, the STM32 exchanges data with a PC host through USB interface in Device mode.
 - On the other side, the STM32 exchanges data with other devices (same host, other host,
 other devices…) through the UART interface (JP4).
 
At the beginning of the main program the HAL_Init() function is called to reset all the peripherals,
initialize the Flash interface and the systick. The user is provided with the SystemClock_Config()
function to configure the system clock (SYSCLK) to run at 80 MHz. The Full Speed (FS) USB module uses
internally a 48-MHz clock which is coming from a specific output of two PLLs (PLL or PLL SAI) or from MSI
 
When the VCP application is started, the STM32 MCU is enumerated as serial communication port and is
configured in the same way (baudrate, data format, parity, stop bit) as it would configure a standard 
COM port. The 7-bit data length with no parity control is NOT supported.
 
During enumeration phase, three communication pipes "endpoints" are declared in the CDC class
implementation (PSTN sub-class):
 - 1 x Bulk IN endpoint for receiving data from STM32 device to PC host:
 When data are received over UART they are saved in the buffer "UserTxBuffer". Periodically, in a 
 timer callback the state of the buffer "UserTxBuffer" is checked. If there are available data, they
 are transmitted in response to IN token otherwise it is NAKed.
 The polling period depends on "CDC_POLLING_INTERVAL" value.
 
 - 1 x Bulk OUT endpoint for transmitting data from PC host to STM32 device:
 When data are received through this endpoint they are saved in the buffer "UserRxBuffer" then they
 are transmitted over UART using interrupt mode and in meanwhile the OUT endpoint is NAKed.
 Once the transmission is over, the OUT endpoint is prepared to receive next packet in
 HAL_UART_TxCpltCallback().
 
 - 1 x Interrupt IN endpoint for setting and getting serial-port parameters:
 When control setup is received, the corresponding request is executed in CDC_Itf_Control().
 In this application, two requests are implemented:
 - Set line: Set the bit rate, number of Stop bits, parity, and number of data bits 
 - Get line: Get the bit rate, number of Stop bits, parity, and number of data bits
 The other requests (send break, control line state) are not implemented.
 
@note Receiving data over UART is handled by interrupt while transmitting is handled by DMA allowing
 hence the application to receive data at the same time it is transmitting another data (full- 
 duplex feature).
 
The support of the VCP interface is managed through the ST Virtual COM Port driver available for 
download from www.st.com.
 
@note The user has to check the list of the COM ports in Device Manager to find out the number of the
 COM ports that have been assigned (by OS) to the VCP interface.
 
This application uses UART as a communication interface. The UART instance and associated resources
(GPIO, NVIC) can be tailored in "usbd_cdc_interface.h" header file according to your hardware 
configuration. Moreover, this application can be customized to communicate with interfaces other than UART.
For that purpose a template CDC interface is provided in: 
Middlewares/ST/STM32_USB_Device_Library/Class/CDC/Src directory.
 
To run this application, the user can use the following configuration:
 
 Connect USB cable to Host and connect UART TX pin to UART RX pin on the STM32L496G-Discovery board
 (Loopback mode). In this case, you can open one terminal (relative to USB com port)
 and all data sent from this terminal will be received by the same terminal in loopback mode.
 This mode is useful for test and performance measurements.
 
@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
 based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
 a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
 than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
 To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
 
@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
 to have correct HAL operation.
 
For more details about the STM32Cube USB Device library, please refer to UM1734 
"STM32Cube USB Device library".
 
@par Directory contents 
 
 - USB_Device/CDC_Standalone/Src/main.c Main program
 - USB_Device/CDC_Standalone/Src/system_stm32l4xx.c STM32L496xx system clock configuration file
 - USB_Device/CDC_Standalone/Src/stm32l4xx_it.c Interrupt handlers
 - USB_Device/CDC_Standalone/Src/stm32l4xx_hal_msp.c HAL MSP module
 - USB_Device/CDC_Standalone/Src/usbd_cdc_interface.c USBD CDC interface
 - USB_Device/CDC_Standalone/Src/usbd_conf.c General low level driver configuration
 - USB_Device/CDC_Standalone/Src/usbd_desc.c USB device CDC descriptor
 - USB_Device/CDC_Standalone/Inc/main.h Main program header file
 - USB_Device/CDC_Standalone/Inc/stm32l4xx_it.h Interrupt handlers header file
 - USB_Device/CDC_Standalone/Inc/stm32l4xx_hal_conf.h HAL configuration file
 - USB_Device/CDC_Standalone/Inc/usbd_conf.h USB device driver Configuration file
 - USB_Device/CDC_Standalone/Inc/usbd_desc.h USB device CDC descriptor header file
 - USB_Device/CDC_Standalone/Inc/usbd_cdc_interface.h USBD CDC interface header file 
 
 
@par Hardware and Software environment
 
 - This example runs on STM32L496xx devices.
 
 - This example has been tested with STMicroelectronics STM32L496G-Discovery RevA 
 board and can be easily tailored to any other supported device and development board.
	
 - STM32L496G-Discovery RevA Set-up
 - Connect the STM32L496G-Discovery board to the PC through 'USB micro A-Male 
 to A-Male' cable to the connector CN8 to use USB Full Speed (FS)
 - For loopback mode test: connect directly USART TX PB6: pin 2 in CN2 and RX pins PB7: pin D14 in CN10
 
 - Hyperterminal configuration:
 - BaudRate = 115200 baud
 - Word Length = 8 Bits
 - Stop Bit = 0
 - Parity = None
 - Flow control = None 
 
 
@par How to use it ?
 
In order to make the program work, you must do the following :
 - Open your preferred toolchain 
 - Rebuild all files and load your image into target memory
 - Run the application
 - Install the USB virtual COM port driver
 - Find out the number of the COM port assigned to the STM32 CDC device
 - Open a serial terminal application and start the communication
 
 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */

board closest to the selected STM32, USB example which typically is a USB to USART bridge functionality.

Example:

C:\CUBE RELATED\STM32Cube_FW_L4_V1.12.0\Projects\32L496GDISCOVERY\Applications\USB_Device\CDC_Standalone