I found and fixed the problem. The application that didn't work sent a data byte and immediately checked cts only once. If cts wasn't immediately high after sending the byte, it generated an error. I initially fixed the problem by introducing a time delay before checking cts. I'll convert it to a polled check in the near future. I suspect what happened is that someone improved the performance of the USB serial driver and thus it was done sending faster than it previously was. This caused it to check cts before it changed states and thus the error. As far as I can tell, the current USB serial driver for a PL2303 device (as of 2.6.10-1.727_FC3) works fine. Hope this helps someone. On Wed, 2005-01-05 at 11:37 -0700, Kim Lux wrote: > I've got an application that talks to a device via a USB serial port. > (PL2301 device.) > > It worked fine a few weeks ago. Now it doesn't. I can still use > minicom to talk with the device. The error I get with the application > is a cts timeout error. > > I checked the port using stty and hardware handshaking is set with both > applications, ie the one that doesn't work and minicom. > > Any ideas on how to proceed would be appreciated. > > I think I saw a post or two about someone else having a similar problem, > but I can't find it. I think it was on this list. Does anyone remember > it ? > > Thanks. > -- Kim Lux, Diesel Research Inc.
