1.Only Timer 0 interrupt is enabled in the system and it is assigned a priority of 1. It is observed that the timer interrupt occurred only once and it is not occurring even though the timer roll over happens. The program does not contain any instruction for disabling the global interrupt enable flag IE and Timer 0 interrupt. What could be the reason? What are the different addressing modes supported by 8051?
(a) Direct Addressing (b) Indirect Addressing
(c) Register Addressing (d) Indexed Addressing
(e) Immediate Addressing (f) All of these
2. Which is the addressing mode for the instruction MOV A, #50H
(a) Direct (b) Indirect (c) Immediate (d) None of these
3. Which is the addressing mode for the instruction MOV A, 50H
(a) Direct (b) Indirect (c) Immediate (d) None of these
4. Which is the addressing mode for the instruction MOV A, @R0
(a) Direct (b) Indirect (c) Immediate (d) None of these
5. Which is the addressing mode for the instruction MOVC A, @A+DPTR
(a) Direct (b) Indirect (c) Immediate (d) None of these
