Hi, Could you help me please. Do you know how this offset is written without using "_at_" keywords. this developpment compiled and run properly on an older compiler (CC51).It is using 2 bank register, signal and serial interrupt, and is coded in asm with C. I link with LX51. the MAP file generated indicate this: < START STOP LENGTH ALIGN RELOC MEMORY CLASS SEGMENT NAME * * * * * * * * * * * C O D E M E M O R Y * * * * * * * * * * * * * 000582H 000584H 000003H --- OFFS.. CODE ?CO?LETM?14 *** OVERLAP *** 000583H 000585H 000003H --- OFFS.. CODE ?CO?LETM?15 > ROM:from 0x0000 to: 0x8000 RAM:from 0x0000 to: 0x2000 I even change the start of ROM (to see) and these adresses and error stay the same. I don't understand this problem. Thanks (nota: I'm french)