I've developed a firmware to run on 22-bit contiguous mode of DS80C390. In the "debug" property sheet of "options for target" window, I've added the "-C390" parameter for "S8051.DLL". However, in the debug session, it has the problems below :- 1) the disassembler window failed to display 22-bit assembler instructions 2) the debugger failed to step over C source lines (if it contain 22-bit assembler instructions) My uVision2 is PK51 V2.40a. Can you advice how to correct these problem ?