I use the MCB900 prototype board (revision E). My source code is in assembler (.a51) When I debbug my code with µvision2 software, I have No errors, No Warning, and all the interrupts are abble to exit the total power down mode. But when I run the application with the MCB900 (P89LPC932 MCU), the system stay on the power down mode and nothing can get out the MCU from it. Is it a bug on the MCB900 prototype board or am I mad ? Thanks for your response, Dorian.