For 8 months now I've been having an occaisional but annoying problem connecting uVision debugger to my C167 via the RS-232 serial port and Monitor-167. It simply wouldn't connect, and when I hit Stop Debugging uVision would crash. I think I've finally solved the problem, after finding a knowledgebase article about DScope. Symptoms: uVision would occasionally say Connection To Target System Lost! when it shouldn't have. There was no hardware problem because Phytec's Flashtools connected just fine every single time. I found that I had to reboot, connect Flashtools, then disconnect, then connect uVision, then reboot (don't reboot before connecting uVision), then hit Try Again to connect uVision. From these symptoms, I expect that uVision's Monitor-167 interface serial port handling is poorly done. This was using Win2K on an IBM A31. Solution: Fix up the Windows properties for the serial port: 1. Disable the serial port FIFO. 2. Set the baud rate for the port above that required by uVision. 3. Turn off all flow control for the port. Doing this seems to have eliminated the problem. I hope this helps someone out there.