Homework 1 : Solution
1. None
2. None
3.
a) 27 = 1*1 + 1*2 + 1*8 + 1*16
b) 124 = 4*1 + 7*8 + 1*64
c) 1016 = 8*1 + (F=15)*16 + 3*256
d) 13.6875 = 1*8 + 1*4 + 1*1 + 1*(1/2) + 1*(1/8) + 1*(1/16)
4.
a)254 --> 11111110
254/2 =
127 R0
127/2 =
63 R1
63/2 =
31 R1
31/2 =
15 R1
15/2 =
7 R1
7/2 =
3 R1
3/2 =
1 R1
1/2=
0 R1
b)174o --> 001 111 100
1->001
7->111
4->100
c)2.4375 --> 10.0111
//Decimal
portion evaluation
.4375 * 2 = .875
--> 0
.875 * 2 =
1.75 --> 1
.75 * 2 =
1.5 --> 1
.5 * 2 =
1.0 --> 1
d))0C5h --> 1100 0101
C --> 1100
5
--> 0101
5.
a) 1
15o
+53o
---------
70o
b) 1111
0001
+1001
00111
---------
10001
c) 110100
-011010
-------------
11010
d) 101
x 011
------------
101
1010
+ 000
--------------
1111
6.
a) -26 --> 111010
First, convert 26 to binary -->
11010
Next, tack on the sign bit, in this
case negative = 1
Answer : 111010
b) -26 --> 100110
First, convert 26 to binary, using 6
bits --> 011010
Now flip the bits --> 100101
Finally add 1 --> Answer :
100110
c) Smallest : -128
Largest
: 127
d) 11111100 --> 1100
7.
a) -6 --> 1010 in 2s
complement
Boolean Expression : x8 + ~x4 + x2 +
~x1
b) Logic Circuit :
8.
State |
Next State |
New |
Equal |
Mux |
Open/Closed |
S1 |
S1 |
0 |
X |
C1 |
close |
S1 |
E2 |
1 |
0 |
C1 |
close |
S1 |
S2 |
1 |
1 |
C1 |
close |
S2 |
S2 |
0 |
X |
C2 |
close |
S2 |
E3 |
1 |
0 |
C2 |
close |
S2 |
S3 |
1 |
1 |
C2 |
close |
S3 |
S3 |
0 |
X |
C3 |
close |
S3 |
CLOSE |
1 |
0 |
C3 |
close |
S3 |
OPEN |
1 |
1 |
C3 |
open |
E2 |
E2 |
0 |
X |
- |
close |
E2 |
E3 |
1 |
X |
- |
close |
E3 |
E3 |
0 |
X |
- |
close |
CLOSE |
OPEN |
- |
- |
- |
open |
OPEN |
CLOSE |
- |
- |
- |
close |
Most likely, an external reset would be required to
take the lock from the Open/Close state -> S1