I'm using keil c51 7.05 Problem is that uVision can connect to mon51 only in win98 environment. In win2000, or winxp it fails to connect. Does any body have solution? TIA!
"where is userport.sys ?" Given that Keil support themselves don't have it, this appears to be a red herring. However, you still haven't answered the questions about your serial port hardware.