M.C.A.(Science)(Semester-I) (CBCS) Examination, 2017
Digital Circuits and Microprocessors
Day Date: Tuesday, 25-04-2017 Max. Marks: 70
Time: 10.30 AM to 01.00 PM
Instructions
Q.1 and Q.2 are compulsory
Attempt any Three Questions from Q.3 to Q.7
Figures to the right indicate full marks.
Q.1 Choose the correct alternatives 10
Which is the basic stack operation
PUSH POP
Both a and b None of these
Which technology using the microprocessor is fabricated on
a single chip
POS MOS
ALU ABM
A combinational circuit that selects one from many inputs
encoder decoder
mux None of the above
The main difference between JK and RS flip-flop is that
JK flip-flop does not need a clock pulse
JK flip-flop is acronym of junction cathode multivibrator
JK flip-flop accepts both inputs as 1
None of the above
How many truth table entries are necessary for a four-input
circuit
16 12 E
8 None of these
A simple flip-flop
Is a four state device Is 2 bit memory
has nothing to do with memory None of the above
How many different states does a 3-bit asynchronous counter
have
8 4 E
16 None of the above
Page 2 of 2
The CF is known as
Condition flag Common flag E
Carry flag None of the above
NOP instruction introduces
Address Delay E
Memory location None of the above
10)


Y Gives

None of these
State true or false: 04
Data transfer group of instructions does not affect the flags
INC destination increments the content of destination by 1
Control bus is bidirectional.
The IP is 8 bits in length.
Q.2 What is decoder? Explain 3:8 decoder. 08
Write 8085 program to exchange contents of two memory
locations.
06
Q.3 What is multiplexer? Explain 4:1 multiplexer. 08
Explain working of T Flip-Flop. 06
Q.4 Explain Buffered system bus of 8086 in minimum mode. 08
Draw timing diagram for LXI instruction 06
Q.5 What is register? Explain 4-bit serial in parallel out shift register. 08
Explain derived logic gates. 06
Q.6 What is counter? Explain 2-bit ripple up asynchronous counter. 08
Explain working of half subtracter. 06
Q.7 Explain stack and machine control instructions of 8085. 08
Explain code segment and stack segment of 8086. 06