I have a program working on 89c51.Since i wanted to introduce a watch dog scheme I need to use 89s8252.

Now the programme that was running on 89c51 refuses to run properly with 89s8252.Note that I have not enabled the wwatch dog circuit. The problem seems to be erratic and the data coming out of the serial port is not the same as from 89c51. Are there any register/bit which are to be initialised differently in 89s8252 as against 89c51.