Hi all I've just started using Keil C51. The first thing I did was to try an compile an example which I already had its hex file(this was compiled by Keil as well). the problem is that when I comiled the source code using Keil it compiled and linked fined and generated a hex file, however, this hex file is not working as expected ... I made sure that I am using the right device and the right configuration. can anybody help? Thanks