LINA01 UPDATED EXAM QUESTIONS AND
CORRECT ANSWERS
●● Convert the decimal number #-476 to a 12-bit two's complement
binary number, and
represent the result as hexadecimal
Answer: xE24
●● Given the instruction (located at address x3500)
x3500 LDI R1, label1
and given:
label1 translates to address x35A0, which contains the value xC000;
memory location xC000 contains the value xD000;
memory location xD000 contains the value xFFFF;
What value will R1 contain after the instruction executes?
Answer: xD000
●● Simplify the Boolean expression:
a.b'.c'.d + a.b'.c.d + a.b.c'.d + a.b.c.d' + a.b.c.d
Answer: a.d + a.b.c
,●● How many memory locations can be addressed by a microprocessor
that uses 24 bit
addressing?
Answer: 16 M
●● How many select lines does an 8 input multiplexer have?
Answer: 3
●● How many input lines does an 8 input multiplexer have?
Answer: 8
●● How many output lines does an 8 input multiplexer have?
Answer: 1
●● How many inputs does a full adder circuit have?
Answer: 3
●● A "gate delay" can be described as the time needed for the output of
a gate to settle to its
correct level after one of its inputs has been changed. The full-adder
circuit we have
designed would therefore result in a gate delay of 2 units.
How many units of gate delay would a 4-bit ripple-adder display?
, Answer: 8
●● How do we turn 8 separate gated D-latches into a single 8-bit
register?
(WE = "Write Enable")
Answer: connect their WE lines together to a single external WE
●● How do we turn 8 separate gated D-latches into 8 addressable
registers, each 1-bit wide?
Answer: connect the WE of each one separately to an output of a 3-bit
decoder, and multiplex their outputs with
the same decoder
●● The following very complex subroutine moves the cursor down to
the next line. What, if
anything, is wrong with it?
.ORIG x4000
NEWLINE LD R0, CRLF
OUT
RET
CRLF .FILL x0A
Answer: c. it should save and restore the contents of R0
d. it should save and restore the contents of R7
CORRECT ANSWERS
●● Convert the decimal number #-476 to a 12-bit two's complement
binary number, and
represent the result as hexadecimal
Answer: xE24
●● Given the instruction (located at address x3500)
x3500 LDI R1, label1
and given:
label1 translates to address x35A0, which contains the value xC000;
memory location xC000 contains the value xD000;
memory location xD000 contains the value xFFFF;
What value will R1 contain after the instruction executes?
Answer: xD000
●● Simplify the Boolean expression:
a.b'.c'.d + a.b'.c.d + a.b.c'.d + a.b.c.d' + a.b.c.d
Answer: a.d + a.b.c
,●● How many memory locations can be addressed by a microprocessor
that uses 24 bit
addressing?
Answer: 16 M
●● How many select lines does an 8 input multiplexer have?
Answer: 3
●● How many input lines does an 8 input multiplexer have?
Answer: 8
●● How many output lines does an 8 input multiplexer have?
Answer: 1
●● How many inputs does a full adder circuit have?
Answer: 3
●● A "gate delay" can be described as the time needed for the output of
a gate to settle to its
correct level after one of its inputs has been changed. The full-adder
circuit we have
designed would therefore result in a gate delay of 2 units.
How many units of gate delay would a 4-bit ripple-adder display?
, Answer: 8
●● How do we turn 8 separate gated D-latches into a single 8-bit
register?
(WE = "Write Enable")
Answer: connect their WE lines together to a single external WE
●● How do we turn 8 separate gated D-latches into 8 addressable
registers, each 1-bit wide?
Answer: connect the WE of each one separately to an output of a 3-bit
decoder, and multiplex their outputs with
the same decoder
●● The following very complex subroutine moves the cursor down to
the next line. What, if
anything, is wrong with it?
.ORIG x4000
NEWLINE LD R0, CRLF
OUT
RET
CRLF .FILL x0A
Answer: c. it should save and restore the contents of R0
d. it should save and restore the contents of R7
