Need CDC-ACM (libusb, HS) Sample, Without UART for STM32U5 – For Real-Time DCMI Data.

[saikumar]

Hi ST Community,

I'm working with the STM32U5G9ZJT6Q and need to send real-time data from DCMI over USB through CDC . I generated a CDC-ACM project using CubeMX 6.14.0, and by default, it appears as a Virtual COM Port under device manager . Then i used Zadig to replace the driver with libusb-win32, and now the device shows up under libusb devices, ready for high-speed (HS) USB communication.

However, all CDC-ACM examples I’ve found using with UART, which doesn’t meet the performance needs for my video streaming use case.

I’m requesting a sample project or reference code using the STM32U5 USB stack, where CDC-ACM works with libusb (HS mode) and does not rely on UART, so I can send DCMI data directly over USB.

thanks,

[FBL]

Hi @saikumar 

While we can't provide a specific example for every request, we can assist you in customizing your project using reference board STM32U5G9J-DK2. Start with this example provided for CDC interface and let us assist you troubleshooting issues. Consider sharing minimum project so we can identify the specific problem you're encountering.

[saikumar]

hello, mr @FBL 

thanks for your reply,

• In my earlier project: i used STM32H743ZI2 MCU for  ( USB CDC communication on High speed mode ).
• By default the code provided proper initialization for USB endpoints, User don't need write  any initialization for receive and transmit . 

      The following functions were available 

• static int8_t CDC_Receive_HS(uint8_t* Buf, uint32_t *Len);
  (This function was triggered via interrupt whenever the host sent data)
• uint8_t CDC_Transmit_HS(uint8_t* Buf, uint16_t Len);
  (Used to send data back to the host
• This made it easy to handle host-to-device and device-to-host USB communication entirely via USB, without using UART.

Now I am using STM32U5  series, as this stack is different .

1. The callbacks USBD_CDC_ACM_Activate(), Deactivate(), and ParameterChange() are generated empty  
2. The device enumerates as a Virtual COM Port by default.
3. When I switch the driver using Zadig to WinUSB (libusb), the device is detected correctly under “libusb-win32 devices,” but no data transmission or reception occurs .  the problem is i don't know how to initialize USBD_CDC_ACM_Activate(), Deactivate(), and ParameterChange() , and   usbx_cdc_acm_write_thread_entry(ULONG thread_input) ,  and  usbx_cdc_acm_read_thread_entry(ULONG thread_input).      functions for my problem  . 

so could you please provide code  to properly initialize the USB CDC_ACM interface for  USB (lib_usb)  use without using UART.

How to set up the  reception and transmission, similar to how CDC_Receive_HS() and CDC_Transmit_HS() worked in my previous working H743ZI2 project.

i uploaded codes for reference.

thanks.

[FBL]

Hello @saikumar 

This example uses classic middleware on STM32U5. If you consider using USBX stack, I recommend this example. I'm not sure which driver (lib_usb) will it point.

• On one side, the STM32 exchanges data with a PC host through USB CDC interface in Device mode.
• On the other side, the STM32 exchanges data with ST-LINK MCU through UART which could be customized according to your specific requirements.

[saikumar]

hello, mr @FBL 

Actually, I have the same requirement as mentioned in this post:

"https://community.st.com/t5/stm32-mcus-embedded-software/how-to-implement-winusb-instead-of-cdc-acm-on-stm32u5-series-mcu/m-p/805629#M63864"

In your reply, you mentioned that we need to use  "https://github.com/STMicroelectronics/stm32u5-classic-coremw-apps/tree/main " .

I would like to ask :- instead of requiring a total stack change, is it not possible to update the existing STM32U5 series USB device stack to support WinUSB functionality directly?

This would help a lot , who are already using the default USB stack generated by STM32CubeMX for STM32U5 and want to use WinUSB without major modifications.

Looking forward to your input.

Thanks.