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Arduino Cookbook by Michael Margolis

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Appendix G. ASCII and Extended Character Sets

ASCII stands for American Standard Code for Information Interchange. It is the most common way of representing letters and numbers on a computer. Each character is represented by a number—for example, the letter A has the numeric value 65, and the letter a has the numeric value 97 (lowercase letters have a value that is 32 greater than their uppercase versions).

Values below 32 are called control codes—they were defined as nonprinting characters to control early computer terminal devices. The most common control codes for Arduino applications are listed in Table G-1.

Table G-1. Common ASCII control codes

Decimal

Hex

Escape code

Description

0

0x0

'\0'

Null character (used to terminate a C string)

9

0x9

'\t'

Tab

10

0xA

'\n'

New line

13

0xD

'\r'

Carriage return

27

0x1B

 

Escape

Table G-2 shows the decimal and hexadecimal values of the printable ASCII characters.

Table G-2. ASCII table
 

Dec

Hex

 

Dec

Hex

 

Dec

Hex

Space

32

20

@

64

40

`

96

60

!

33

21

A

65

41

a

97

61

"

34

22

B

66

42

b

98

62

#

35

23

C

67

43

c

99

63

$

36

24

D

68

44

d

100

64

%

37

25

E

69

45

e

101

65

&

38

26

F

70

46

f

102

66

'

39

27

G

71

47

g

103

67

(

40

28

H

72

48

h

104

68

)

41

29

I

73

49

i

105

69

*

42

2A

J

74

4A

j

106

6A

+

43

2B

K

75

4B

k

107

6B

,

44

2C

L

76

4C

l

108

6C

-

45

2D

M

77

4D

m

109

6D

.

46

2E

N

78

4E

n

110

6E

/

47

2F

O

79

4F

o

111

6F

0

48

30

P

80

50

p

112

70

1

49

31

Q

81

51

q

113

71

2

50

32

R

82

52

r

114

72

3

51

33

S

83

53

s

115

73

4

52

34

T

84

54

t

116

74

5

53

35

U

85

55

u

117

75

6

54

36

V

86

56

v

118

76

7

55

37

W

87

57

w

119

77

8

56

38

X

88

58

x

120

78

9

57

39

Y

89

59

y

121

79

:

58

3A

Z

90

5A

z

122

7A

;

59

3B

[

91

5B

{

123

7B

<

60

3C

\

92

5C

|

124

7C

=

61

3D

]

93

5D

}

125

7D

>

62

3E

^

94

5E

~

126

7E

?

63

3F

_

95

5F

   

Characters above 128 are non-English characters or special symbols ...

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