I have translated a code from hex to 8051set instructions.But the code was written in assembly code for 80c552.So,I have some problems in reading the code because the assembler(A51) doesn't recognize some registers or flags like: EXEN2,CSR,TR2.If you konw what does these mean for 80c552 please help me.I want to say that I obtained a code which contains SBUF(for serial comunication specific to 8051,the existing of this file generated to me some errors) and I replaced it with S0BUF(specific to 80c552) and the errors was gone.