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Hello,
i´m working on a K-Line interface using a STM32F105. The middleware lib is successfully installed and the virtual com port is running good with the CDC ACM feature.
Now there is a special problem. The KWP2000 protocol is using a special RS232 feature called send line break condition. There is a SEND_BREAK request (23h) send from Windows via the usbser.sys driver to the middleware library. So the cortex as to apply a positiv voltage on the rs-232 tx-line.
I could´t find the point or the function which is called or is it not implemented in the usb device class?
Hey Milorad, thanks for the fast answer. I have already testet some "Core" functions but they are all already defined in the compiled USB_CM3.lib. I think they are translated in the library from USBD_CDC_ACM_CoreSendBreak to USBD_CDC_ACM_SendBreak but i couldn´t verify it because it has never been called.
Are you sure the SendBreak funktion is the right way ?
I´m looking for the function in the CDC ACM which is called when windows send "IOCTL_SERIAL_SET_BREAK_ON" for example.
Maybe the "USBD_CDC_ACM_Core_SendBreak" is the way back to the usb-host ???
Hi Wolf,
the only thing that CDC offers regarding break signalling is SEND_BREAK command 23h, which is specified in details in PSTN120.pdf from USB.org file.
If you are able to see USB traffic then when you do your mentioned "IOCTL_SERIAL_SET_BREAK_ON" you should be able to see control endpoint 0 request SEND_BREAK.
That request will be passed to USBD_CDC_ACM_CoreSendBreak function which if you implement it will do whatever you implement.