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rust-embedded-community / usbd-serial

Work-in progress minimal CDC-ACM (USB serial port) class for usb-device
MIT License
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Device Terminal Ready (DTR) is not resetting #22

Closed chris-ricketts closed 2 years ago

chris-ricketts commented 2 years ago

Hi, I'm using usbd-serial on the NordicSemi NRF52840 and it's working pretty well.

To detect when there is a terminal connected on the host I use the SerialPort::dtr function so the buffer is not filled with stale data. This works well but the flag is not reset when the terminal disconnects. I make sure to poll the device between checking the flag. Is this behavior expected?

If so, do you know of another way to detect the terminal disconnecting?

mvirkkunen commented 2 years ago

What are you disconnecting from what when "the terminal disconnects"? Are you disconnecting the USB cable or something else that's plugged into your microcontroller?

chris-ricketts commented 2 years ago

Apologies for being ambiguous.

By a terminal, I mean a program on the host that has opened the serial port. For example, I am testing with screen /dev/ttyACM0 115200.

By disconnecting, I mean the program closing the serial port. E.g. ending that screen session but not unplugging the USB device.

The NRF52840 is going to be in a dongle form so it will always be plugged in with the SerialPort setup.

chris-ricketts commented 2 years ago

Closing as this as it is dependent on the program opening the serial port on the host. Testing with PuTTY the DTR flag is reset as expected when the session is closed.

mvirkkunen commented 2 years ago

On Linux that might also be dependent on your terminal settings. You can probably get Linux to do the same with stty or such.