If you happen to be writing in C51 this is very easliy done with atoi() or with sscanf() and then sprintf().

You can find code here as Dan suggested, if you are working in assembly language.

It is also possible to find code using a search engine. If you used Google with a search key of decimal to hex conversion on 8051 you get about 900 hits!! And the first one on the search I did was the 8052.com Code Library page!!

Please search before posting questions like this here. It appears that you are a beginner and one thing to get very used to is that Google will become your best friend.

Michael Karas