TM4C129XNCZAD: USB CDC device class-specific request to read the virtual handshaking signals (CTS, DSR, RI, DCD)

Hello Andrey,

I need to look into this in more detail in the office tomorrow, but for starters, please make sure you are referring to our USB Library guide for TivaWare which is up-to-date with our current offering: http://www.ti.com/lit/ug/spmu297d/spmu297d.pdf

A quick search in that document didn't show me much to indicate it has more information but that is the latest documentation. I will see what else I can do to shed light on the functionality you are seeking provided it exists in the TivaWare UsbLib.

Hi Ralph,

I found this document a little later, but it also does not describe this point.

Hi Ralph,

Thanks for a link, but she is useless:

The example does not implement the following:

• No CTS/RTS control is performed, so flow control must be set to nonein the terminal program.
• RTS/DTR control is not implemented

also I found this topic http://www.utasker.com/forum/index.php?topic=794.0 see first response. It seems to me that is why in your documentation there is no description and in the library there are no functions for reading state this signals

Hello Andrey,

Yeah that could be why. I do know the captures I have of USB communication include using the Get Line and Set Line Coding commands and Set Control Line State as well.

The CDC-ACM documentation for USB developers is probably your best bet to understand exactly how all of that works together, I never delved into the specifics of those signals and haven't read the developer documentation (I didn't write usblib, only support it as it exists today).