I m writing program for USB host Virtual com port(LPC1768). May be this question found silly but this is confusing me.
Im getting frames correctly upto get line coding After that host is not responding to the device.I m continously getting NACK after every IN after get line coding.
Second issue is i can see the comp port in com port list. I installed drivers through inf file. But when i tried to open the comp port it shows "error: unable to open the com port".reasone for this is the code issue or the drivers issue.
I m bit confuse with the flow of frames in the virtual com port. can any one tell me the flow of frames.which will be the next frame after get line coding.what happened when this frame comes in a picture in hardware point of view.
I don't know much about USB and USBCDC. I had some experience in USBCDC development, but it was long ago (2010). And during that period, I had access to an TotalPhase Beagle USB 480 Protocol Analyzer; now I have nothing.
I would suggest you to use a working well USBCDC device, and an USB Analyzer, study how it works by looking at the class level communication monitored by USB Analyzer. Comparing the difference between the working well device and your device.