Serial Terminal Program for Windows 10

When working with USB devices on Windows 10, it's essential to understand how to detect when the host has opened the device. This is particularly crucial when you need to buffer data until the device is opened and ready for communication.

In the context of a serial terminal program, this challenge arises from the fact that the `ep0_state` value in the USB device driver does not always accurately indicate whether the connection is open or not. On Windows 10 hosts, the `v_state` value becomes `USBD_STATE_CONFIGURED` after the device is configured, regardless of whether the connection is established.

The issue arises when you need to detect whether the host has opened the device before sending data. If there is no listener running on the host, your program may hang or return a busy error (USBD_BUSY) when trying to send characters. On the other hand, if a terminal program is running on the host, you can successfully send characters.

To overcome this limitation, it's essential to implement a mechanism that detects when the host has opened the device and buffers data accordingly. One possible approach is to use a combination of `ep0_state` and `v_state` values to determine the connection status.

In your specific case, since you're using an STM32F723IET6 microcontroller with the internal HS USB as a device, you may need to modify the code to account for the differences in behavior between Windows 10 and Linux hosts. The key is to understand how the `ep0_state` value changes when the connection is opened or closed, and use this information to buffer your data accordingly.

In summary, implementing a reliable serial terminal program on Windows 10 requires careful consideration of the USB device driver's behavior and the need to detect when the host has opened the device. By understanding how to interpret the `ep0_state` and `v_state` values, you can develop a robust solution that buffers data correctly and ensures seamless communication between your device and the host computer.

Serial terminal program windows 10