Data is the raw facts entered into a computer system. Information is data that has been ordered and given some meaning by people. Digital data has discrete steps eg the results of throwing a die is 1,2,3,4,5 or 6, nothing inbetween. Analogue data is continuous without the steps eg the volume control on a radio.

 

5.1 Data representation-number systems

The binary system is also called base 2. It can only use 0 and 1 as the digits. Octal is called base 8. It has 8 digits, 0,1,2,3,4,5,6 & 7. Hexadecimal is base 16. It has 16 digits,0,1,2,3,4,5,6,7,8,9,A,B,C,D,E & F.

 

Decimal	Binary	Octal	Hex
0	0	0	0
1	1	1	1
2	10	2	2
3	11	3	3
4	100	4	4
5		5	5
6		6	6
7		7	7
8		10	8
9		11	9
10		12	A
11		13	B
12		14	C
13		15	D
14			E
15			F
16			20
17			21
18
19
20
22
23
24
25
26
27
28
29
30
31
32

 

7 SEGMENT DISPLAY

This is an array of seven independently controlled light-emitting diodes(LED) or liquid crystal display(LCD). This array is in the shape of the figure 8. It can be used to display numbers and letters.

Each segment is given a letter from a to g so that it can be identified when wiring up.

 

We can draw the circuit diagram for a LED display. There are two types COMMON ANODE and COMMON CATHODE.

  

 

We turn on the LEDs according to the number or letter we are trying to make

   The number 4 needs f,g,b and c ON and a,e and d OFF.

   The letter A needs e,a,b,c and g ON and d OFF.

     

            0                                  1                                  2                                  3

     

                        4                                  5                                  6                                  7

     

                        8                                  9                                  A                                 b

     

                        C                                 d                                  E                                  F

No	a	b	c	d	e	f	g	No	a	b	c	d	e	f	g
0								8
1								9
2								A	1	1	1	0	1	1	1
3								b
4	0	1	1	0	0	1	1	C
5								d
6								E
7								F

 

 

True or False? Write out the true sentences and change the false sentences so that they are true.

 

Information is the raw facts entered into a computer system.

There is an important difference between data and information.

Data is represented as analogue or digital

Analogue data is represented in the form of digits or numbers.

Binary code is another name for binary system.

The binary system uses powers of ten.

Binary numbers are ideal for people.

The hexadecimal number system is to the base sixteen.

The hexadecimal number A16 equals 10, as a decimal number.

Hexadecimal code is often preceded by the % (percentage) sign.