HI, i hav written a piece of code tat executes continuously i.e. while(1) In this there r two condition statement: if(SBUF1==0x20||SBUF1==0x7F||SBUF1==0x0FF) { //Statements } else if(SBUF1==0x53||SBUF1==0x73) { //Statements } And in debug mode i change the value of SBUF1 SFR accordingly...however wen i do "step into" it just does not enter either of these loops. Please help in this regard.