first of all thank you for your answers. Here is my situation. We have designed a couples of years ago an electronic board which was working with a Freescale Digital Signal Controller MC56F8002VWL 1M53M. This chips has been replace by a new one (MC56F8002VWL 2M53M). Freescale said this new chip is same fit same fonction as the old one. But why this chips do not work. I do exactly the same programming procedure. To be sure that it is the MC56F8002VWL 2M53M the matter, I have replaced it by the old one and the electronic board is fully functionnal. I'm using CodeWarrior V8.2.3. I think my problem is the file 56F80xx_init.asm. To be clear, I can programme this new chips, I can change it operating mode (Programme or Run) but when it is in Run mode, notting happen!