Hi d_hamen,
thanks for your reply, i have take a look at the thread u had mentioned. Forgive my poor PIC knowledge, i am a newbie to pic world. I found that the friends post their code using some statements like:"Hserin,Hserout....". these statement are new to me. Because i only know the C language and i only can work with MPLAB IDE ,ICD2,C complier-mcc18.(Beacause the lab only provide these softare and hardware) i didn't use the function like that before. i also don't know how to use.So can you give me some idea? Thank you very much.