I'm using the latest keil and philip's debugging tool (PDS51E) with a LPC900 emulator (PDS900). This may be more of a philips question, but I thought some of you may know. I guess, I must not totally understand the process that takes place when an object file is loaded into the debugger. When I load the omf51 object file, I am presented with a "source" window that says "File not found : ?C_STARTUP". Once into main(), my source debugs fine. But why doesn't it know to look into the start900.a51 source? TIA James