Digital-electronics 简明教程

Digital Electronics - ASCII Codes

ASCII 代表 American Standard Code for Information Interchange 。ASCII 编码是一种在数字计算系统中用于字符编码的常用编码方案。

ASCII stands for American Standard Code for Information Interchange. The ASCII code is a popular coding scheme used in digital computing systems to encode characters.

在 ASCII 编码中，为每个字符（如数字、字母、符号等）分配了一个唯一的整数值。标准 ASCII 编码定义了一组 128 个字符，其中每个字符都可以用一个唯一的 7 位二进制代码表示。因此，ASCII 编码可以表示总共 27 = 128 个可能的字符。

In the ASCII code, a unique integer value is assigned to each character like number, letter, symbol, etc. The standard ASCII code defines a set of 128 characters, where each character can be represented by a unique 7-bit binary code. Therefore, ASCII code can represent total 27 = 128 possible characters.

在数字电子产品中，ASCII 编码中的字符通常用十进制或十六进制表示。总体而言，ASCII 编码是用于在数字计算机和通信系统中表示字符的标准编码方案。

In digital electronics, the characters in ASCII code are generally represented in decimal or hexadecimal notation. Overall, the ASCII code is a standard encoding scheme for representing characters in digital computers and communication systems.

Properties of ASCII Code

以下是 ASCII 编码的一些关键特征：

The following are some key characteristics of ASCII code −

ASCII code assigns a unique numeric value to each character.
ASCII code provides a way of representing letters, numbers, symbols, and control characters.
ASCII code is compatible with a wide range of programming languages and digital devices.
ASCII code supports various control characters for basic text formatting and device control.
ASCII code has decimal and hexadecimal representation. Hence, it is human-readable.
ASCII code assigns numeric values to characters in a sequential order, making it an efficient encoding standard in terms of sorting and searching.
ASCII code is highly space efficient and simple.

Types of ASCII Code

ASCII（美国信息交换标准代码）代码基本上是数字电子产品中使用的 7 位字符编码标准。但它随着计算技术的进步而发展。

ASCII (American Standard Code for Information Interchange) code is basically a 7-bit character encoding standard used in digital electronics. But it is evolved with the advancement in computing technologies.

以下是有两种主要类型的 ASCII 代码：

The following are two main types of ASCII codes −

Standard ASCII Code
Extended ASCII Code

让我们首先讨论标准 ASCII 代码。

Let’s discuss the Standard ASCII Codes first.

Standard ASCII Code

它是一个 7 位字符编码标准，范围从 0 到 127，即总共 128 个可能的字符。它为每个字符（包括数字、字母、符号和控制字符）分配一个 7 位唯一的二进制代码。

It is a 7-bit character encoding standard having a range from 0 to 127 i.e., total 128 possible characters. It assigns a 7-bit unique binary code to each character including numbers, letters, symbols, and control characters.

下表以十进制和二进制形式突出显示了从 0 到 127 范围内的名称、符号和 ASCII 代码。

The following table highlights the name, symbol and ASCII code in decimal and binary form for the range from 0 to 127.

Name	Symbol	Decimal	7-Bit Binary
Null char	NUL	0	00000000
Start of Heading	SOH	1	00000001
Start of Text	STX	2	00000010
End of Text	ETX	3	00000011
End of Transmission	EOT	4	00000100
Enquiry	ENQ	5	00000101
Acknowledgment	ACK	6	00000110
Bell	BEL	7	00000111
Back Space	BS	8	00001000
Horizontal Tab	HT	9	00001001
Line Feed	LF	10	00001010
Vertical Tab	VT	11	00001011
Form Feed	FF	12	00001100
Carriage Return	CR	13	00001101
Shift Out / X-On	SO	14	00001110
Shift In / X-Off	SI	15	00001111
Data Line Escape	DLE	16	00010000
Device Control 1 (oft. XON)	DC1	17	00010001
Device Control 2	DC2	18	00010010
Device Control 3 (oft. XOFF)	DC3	19	00010011
Device Control 4	DC4	20	00010100
Negative Acknowledgement	NAK	21	00010101
Synchronous Idle	SYN	22	00010110
End of Transmit Block	ETB	23	00010111
Cancel	CAN	24	00011000
End of Medium	EM	25	00011001
Substitute	SUB	26	00011010
Escape	ESC	27	00011011
File Separator	FS	28	00011100
Group Separator	GS	29	00011101
Record Separator	RS	30	00011110
Unit Separator	US	31	00011111
Space		32	00100000
Exclamation mark	!	33	00100001
Double quotes	"	34	00100010
Hash	#	35	00100011
Dollar	$	36	00100100
Percentage	%	37	00100101
Ampersand	&	38	00100110
Single quote	'	39	00100111
Open parenthesis	(	40	00101000
Close parenthesis	)	41	00101001
Asterisk	*	42	00101010
Plus	+	43	00101011
Comma	,	44	00101100
Hyphen	-	45	00101101
Period, dot or full stop	.	46	00101110
Slash or divide	/	47	00101111
Zero	0	48	00110000
One	1	49	00110001
Two	2	50	00110010
Three	3	51	00110011
Four	4	52	00110100
Five	5	53	00110101
Six	6	54	00110110
Seven	7	55	00110111
Eight	8	56	00111000
Nine	9	57	00111001
Colon	:	58	00111010
Semicolon	;	59	00111011
Less than	<	60	00111100
Equals	=	61	00111101
Greater than	>	62	00111110
Question mark	?	63	00111111
At symbol	@	64	01000000
Uppercase A	A	65	01000001
Uppercase B	B	66	01000010
Uppercase C	C	67	01000011
Uppercase D	D	68	01000100
Uppercase E	E	69	01000101
Uppercase F	F	70	01000110
Uppercase G	G	71	01000111
Uppercase H	H	72	01001000
Uppercase I	I	73	01001001
Uppercase J	J	74	01001010
Uppercase K	K	75	01001011
Uppercase L	L	76	01001100
Uppercase M	M	77	01001101
Uppercase N	N	78	01001110
Uppercase O	O	79	01001111
Uppercase P	P	80	01010000
Uppercase Q	Q	81	01010001
Uppercase R	R	82	01010010
Uppercase S	S	83	01010011
Uppercase T	T	84	01010100
Uppercase U	U	85	01010101
Uppercase V	V	86	01010110
Uppercase W	W	87	01010111
Uppercase X	X	88	01011000
Uppercase Y	Y	89	01011001
Uppercase Z	Z	90	01011010
Opening bracket	[	91	01011011
Backslash		92	01011100
Closing bracket	]	93	01011101
Caret - circumflex	^	94	01011110
Underscore	_	95	01011111
Grave accent	`	96	01100000
Lowercase	a	97	01100001
Lowercase	b	98	01100010
Lowercase	c	99	01100011
Lowercase	d	100	01100100
Lowercase	e	101	01100101
Lowercase	f	102	01100110
Lowercase	g	103	01100111
Lowercase	h	104	01101000
Lowercase	i	105	01101001
Lowercase	j	106	01101010
Lowercase	k	107	01101011
Lowercase	l	108	01101100
Lowercase	m	109	01101101
Lowercase	n	110	01101110
Lowercase	o	111	01101111
Lowercase	p	112	01110000
Lowercase	q	113	01110001
Lowercase	r	114	01110010
Lowercase	s	115	01110011
Lowercase	t	116	01110100
Lowercase	u	117	01110101
Lowercase	v	118	01110110
Lowercase	w	119	01110111
Lowercase	x	120	01111000
Lowercase	y	121	01111001
Lowercase	z	122	01111010
Opening brace	{	123	01111011
Vertical bar			124
01111100	Closing brace	}	125
01111101	Equivalency sign (tilde)	~	126
01111110	Delete		127

Extended ASCII Code

它是一个 8 位字符编码标准，范围从 0 到 255，即总共 256 个可能的字符。扩展 ASCII 代码为标准 ASCII 代码添加了额外的 128 个字符。

It is an 8-bit character encoding standard having a range from 0 to 255 i.e., total 256 possible characters. The extended ASCII code adds extra 128 characters to the standard ASCII code.

下表以十进制和二进制形式显示了从 128 到 255 范围内的名称、符号和 ASCII 代码。

The following table shows the name, symbol and ASCII code in decimal and binary form for the range from 128 to 255.

Name	Symbol	DEC	BIN
Euro sign	€	128	10000000
		129	10000001
Single low-9 quotation mark	‚	130	10000010
Latin small letter f with hook	ƒ	131	10000011
Double low-9 quotation mark	„	132	10000100
Horizontal ellipsis	…	133	10000101
Dagger	†	134	10000110
Double dagger	‡	135	10000111
Modifier letter circumflex accent	ˆ	136	10001000
Per mille sign	‰	137	10001001
Latin capital letter S with caron	Š	138	10001010
Single left-pointing angle quotation	‹	139	10001011
Latin capital ligature OE	Œ	140	10001100
		141	10001101
Latin capital letter Z with caron	Ž	142	10001110
		143	10001111
		144	10010000
Left single quotation mark	‘	145	10010001
Right single quotation mark	’	146	10010010
Left double quotation mark	“	147	10010011
Right double quotation mark	”	148	10010100
Bullet	•	149	10010101
En dash	–	150	10010110
Em dash	—	151	10010111
Small tilde	˜	152	10011000
Trade mark sign	™	153	10011001
Latin small letter S with caron	š	154	10011010
Single right-pointing angle quotation mark	›	155	10011011
Latin small ligature oe	œ	156	10011100
		157	10011101
Latin small letter z with caron	ž	158	10011110
Latin capital letter Y with diaeresis	Ÿ	159	10011111
Non-breaking space		160	10100000
Inverted exclamation mark	¡	161	10100001
Cent sign	¢	162	10100010
Pound sign	£	163	10100011
Currency sign	¤	164	10100100
Yen sign	¥	165	10100101
Pipe, Broken vertical bar	¦	166	10100110
Section sign	§	167	10100111
Spacing diaeresis - umlaut	¨	168	10101000
Copyright sign	©	169	10101001
Feminine ordinal indicator	ª	170	10101010
Left double angle quotes	«	171	10101011
Not sign	¬	172	10101100
Soft hyphen		173	10101101
Registered trade mark sign	®	174	10101110
Spacing macron - overline	¯	175	10101111
Degree sign	°	176	10110000
Plus-or-minus sign	±	177	10110001
Superscript two - squared	²	178	10110010
Superscript three - cubed	³	179	10110011
Acute accent - spacing acute	´	180	10110100
Micro sign	µ	181	10110101
Pilcrow sign - paragraph sign	¶	182	10110110
Middle dot - Georgian comma	·	183	10110111
Spacing cedilla	¸	184	10111000
Superscript one	¹	185	10111001
Masculine ordinal indicator	º	186	10111010
Right double angle quotes	»	187	10111011
Fraction one quarter	¼	188	10111100
Fraction one half	½	189	10111101
Fraction three quarters	¾	190	10111110
Inverted question mark	¿	191	10111111
Latin capital letter A with grave	À	192	11000000
Latin capital letter A with acute	Á	193	11000001
Latin capital letter A with circumflex	Â	194	11000010
Latin capital letter A with tilde	Ã	195	11000011
Latin capital letter A with diaeresis	Ä	196	11000100
Latin capital letter A with ring above	Å	197	11000101
Latin capital letter AE	Æ	198	11000110
Latin capital letter C with cedilla	Ç	199	11000111
Latin capital letter E with grave	È	200	11001000
Latin capital letter E with acute	É	201	11001001
Latin capital letter E with circumflex	Ê	202	11001010
Latin capital letter E with diaeresis	Ë	203	11001011
Latin capital letter I with grave	Ì	204	11001100
Latin capital letter I with acute	Í	205	11001101
Latin capital letter I with circumflex	Î	206	11001110
Latin capital letter I with diaeresis	Ï	207	11001111
Latin capital letter ETH	Ð	208	11010000
Latin capital letter N with tilde	Ñ	209	11010001
Latin capital letter O with grave	Ò	210	11010010
Latin capital letter O with acute	Ó	211	11010011
Latin capital letter O with circumflex	Ô	212	11010100
Latin capital letter O with tilde	Õ	213	11010101
Latin capital letter O with diaeresis	Ö	214	11010110
Multiplication sign	×	215	11010111
Latin capital letter O with slash	Ø	216	11011000
Latin capital letter U with grave	Ù	217	11011001
Latin capital letter U with acute	Ú	218	11011010
Latin capital letter U with circumflex	Û	219	11011011
Latin capital letter U with diaeresis	Ü	220	11011100
Latin capital letter Y with acute	Ý	221	11011101
Latin capital letter THORN	Þ	222	11011110
Latin small letter sharp s - ess-zed	ß	223	11011111
Latin small letter a with grave	à	224	11100000
Latin small letter a with acute	á	225	11100001
Latin small letter a with circumflex	â	226	11100010
Latin small letter a with tilde	ã	227	11100011
Latin small letter a with diaeresis	ä	228	11100100
Latin small letter a with ring above	å	229	11100101
Latin small letter ae	æ	230	11100110
Latin small letter c with cedilla	ç	231	11100111
Latin small letter e with grave	è	232	11101000
Latin small letter e with acute	é	233	11101001
Latin small letter e with circumflex	ê	234	11101010
Latin small letter e with diaeresis	ë	235	11101011
Latin small letter i with grave	ì	236	11101100
Latin small letter i with acute	í	237	11101101
Latin small letter i with circumflex	î	238	11101110
Latin small letter i with diaeresis	ï	239	11101111
Latin small letter eth	ð	240	11110000
Latin small letter n with tilde	ñ	241	11110001
Latin small letter o with grave	ò	242	11110010
Latin small letter o with acute	ó	243	11110011
Latin small letter o with circumflex	ô	244	11110100
Latin small letter o with tilde	õ	245	11110101
Latin small letter o with diaeresis	ö	246	11110110
Division sign	÷	247	11110111
Latin small letter o with slash	ø	248	11111000
Latin small letter u with grave	ù	249	11111001
Latin small letter u with acute	ú	250	11111010
Latin small letter u with circumflex	û	251	11111011
Latin small letter u with diaeresis	ü	252	11111100
Latin small letter y with acute	ý	253	11111101
Latin small letter thorn	þ	254	11111110
Latin small letter y with diaeresis	ÿ	255	11111111

Advantages of ASCII Code

以下是 ASCII（美国信息交换标准代码）代码的主要优点：

The following are the key benefits of the ASCII (American Standard Code for Information Interchange) code −

The ASCII code provides a simple and straightforward encoding scheme to represent letters, numbers, and symbols.
ASCII code is compatible with a wide range of programming languages and computing devices.
ASCII code provides a compact character representation, where each character can be represented using 7-bits or 8-bits. Hence, it is a space efficient encoding standard.
ASCII code is a universally adopted encoding standard in the field of digital electronics.
ASCII code has easy and simple implementation in hardware and software.

Limitations of ASCII Code

ASCII 码有上面描述的几个优点，但它也有一些下面给出的缺点：

ASCII code has several advantages as described above, but it also has some limitations which are given below −

The standard ASCII code has a limited set of 128 characters. This makes it unsuitable for representing characters of languages other than English.
The ASCII code can be extended to 8-bits but it is not standardized beyond 7-bits.
ASCII code is not suitable to use in systems that require a broad range of characters.

Applications of ASCII Code

ASCII 码是一种标准的字符编码方案，用于数字电子领域的广泛应用。

ASCII code is a standard character encoding scheme used in wide range of applications in the field of digital electronics.

ASCII 码的一些主要应用如下：

Some major applications of ASCII code are listed below −

ASCII code is used in digital systems for textual communication.
ASCII code is used in computer programming to represent alphanumeric data like letters, numbers, symbols, etc.
ASCII code is also used in various communication protocols utilized for data transmission among devices.
In the field web technology, ASCII code is used to represent different characters and symbols in a webpage.
ASCII code is also used in database systems to represent text data.

Conclusion

总之，ASCII（美国信息交换标准代码）是一种在数字系统中广泛使用的字符编码方案。它是一个 7 位标准代码，用于表示总共 128 个字符，包括数字、字母、符号和控制字符。

In conclusion, ASCII (American Standard Code for Information Interchange) is a character encoding scheme widely used in digital systems. It is a 7-bit standard code used to represent a total of 128 characters including numbers, letters, symbols, and control characters.