PETSCII

PETSCII (PET Standard Code of Information Interchange), also known as CBM ASCII, is the character set used in Commodore Business Machines' 8-bit home computers.

This character set was first used by the PET from 1977, and was subsequently used by the CBM-II, VIC-20, Commodore 64, Commodore 16, Commodore 116, Plus/4, and Commodore 128. However, the Amiga personal computer family instead uses standard ISO/IEC 8859-1.

History

[edit] The character set was largely designed by Leonard Tramiel (the son of Commodore CEO Jack Tramiel) and PET designer Chuck Peddle. The graphic characters of PETSCII were one of the extensions Commodore specified for Commodore BASIC when laying out desired changes to Microsoft's existing 6502 BASIC to Microsoft's Ric Weiland in 1977. The VIC-20 used the same pixel-for-pixel font as the PET, although the characters appeared wider due to the VIC's 22-column screen. The Commodore 64, however, used a slightly re-designed, heavy upper-case font, essentially a thicker version of the PET's, in order to avoid color artifacts created by the machine's higher resolution screen. The C64's lowercase characters are identical to the lowercase characters in the Atari 8-bit computers font (released 2.75 years earlier).

Peddle claims the inclusion of card suit symbols was spurred by the demand that it should be easy to write card games on the PET (as part of the specification list he received).

Specifications

[edit] "Unshifted" PETSCII is based on the 1963 version of ASCII (rather than the 1967 version, which most if not all other computer character sets based on ASCII use). It has only uppercase letters, an up-arrow ⟨↑⟩ instead of caret ⟨^⟩ at 0x5E and a left-arrow ⟨←⟩ instead of an underscore ⟨_⟩ at 0x5F. In all versions except the original Commodore PET, it also has a British pound sign ⟨£⟩ instead of the backslash ⟨\⟩ at 0x5C. Other characters added in ASCII-1967 (lowercase letters, the grave accent, curly braces, vertical bar, and tilde) do not exist in PETSCII. Codes 0xA0–0xDF are allotted to CBM-specific block graphics characters—horizontal and vertical lines, hatches, shades, triangles, circles and card suits.

PETSCII also has a "shifted" mode (also called "business mode"), which changes the uppercase letters at 0x41–0x5A to lowercase, and changes the graphics at 0xC1–0xDA to uppercase letters. Upper- and lower-case are swapped from where ASCII has them. The mode is toggled by holding one of the SHIFT keys and then pressing and releasing the Commodore key. The shift can be done by POKEing location 59468 with the value 14 to select the alternative set or 12 to revert to standard. On the Commodore 64, the sets are alternated by flipping bit 2 of the byte 53272. On some models of PET, this can also be achieved via special control code PRINT CHR$(14) which adjust the line spacing as well as changing the character set; the POKE method is still available and does not alter the line spacing.

Included in PETSCII are cursor and screen control codes, such as {HOME}, {CLR}, {RVS ON}, and {RVS OFF} (the latter two activating/deactivating reverse-video character display). The control codes appeared in program listings as reverse-video graphic characters, although some computer magazines, in their efforts to provide more clearly readable listings, pretty-printed the codes using their actual names in curly braces, like the above examples. This is unambiguous as PETSCII has no curly brace characters.

Different mappings are used for storing characters (the "interchange" mapping, as used by CHR$()) and displaying characters (the "video" mapping). For example, to display the characters "@ABC" on screen by directly writing into the screen memory, one would POKE the decimal values 0, 1, 2, and 3 rather than 64, 65, 66, and 67.

The keyboard by default provides access to the lower half of the code page. Pressing Shift and a key gives the corresponding upper half code point. Some PETSCII code points cannot be printed and are only used for keyboard input (e.g. F1, RUN/STOP).

Character set

[edit] This article contains uncommon Unicode characters. Without proper rendering support, you may see question marks, boxes, or other symbols instead of the intended characters.

The tables below represent the "interchange" PETSCII encoding, as used by CHR$().

Control characters are defined in the ranges 0x00–0x1F and 0x80–0x9F, although which control characters are defined and what they are defined as varies between systems. The tables below exclude control characters—the encoding of control characters in discussed in § Control characters.

The ranges 0x60–0x7F and 0xE0–0xFF are duplicate ranges, although what they duplicate varies between systems. On the Commodore PET, they duplicate 0x20–0x3F and 0xA0–0xBF, respectively; on the Commodore VIC-20, 64, 16, and 128 they duplicate 0xC0–0xDF and 0xA0–0xBF, respectively. While these characters are visually duplicates, they are semantically different; for example, on the Commodore PET, code points 0x2C and 0x6C both produce a comma character, but only 0x2C functions as a delimiter between input fields.

Graphic characters are mostly identical across systems, with the exceptions of 0x5C (which is \ on the Commodore PET, and £ on other systems), 0xDE (which is U+1FB95 CHECKER BOARD FILL on the Commodore PET and VIC-20, and U+1FB96 INVERSE CHECKER BOARD FILL on other systems), and the range 0x60–0x7F (which duplicates a different range on Commodore PET). Additionally, in Commodore PET 2001's shifted character set, uppercase and lowercase letters are swapped relative to other systems'.

Compatibility symbols for PETSCII characters were added to Unicode 13.0 as part of the Symbols for Legacy Computing block.

Standard

[edit] The following tables represent the PETSCII encoding used on the Commodore VIC-20, 64, 16, and 128.

Unshifted

[edit]

Unshifted PETSCII

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x

1x

2x

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

3x

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

4x

@

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

5x

P

Q

R

S

T

U

V

W

X

Y

Z

[

£

]

↑

←

6x

─

♠

🭲

🭸

🭷

🭶

🭺

🭱

🭴

╮

╰

╯

🭼

╲

╱

🭽

7x

🭾

•

🭻

♥

🭰

╭

╳

○

♣

🭵

♦

┼

🮌

│

π

◥

8x

9x

Ax

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

◤

🮇

├

▗

└

┐

▂

Bx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

🭿

▖

▝

┘

▘

▚

Cx

─

♠

🭲

🭸

🭷

🭶

🭺

🭱

🭴

╮

╰

╯

🭼

╲

╱

🭽

Dx

🭾

•

🭻

♥

🭰

╭

╳

○

♣

🭵

♦

┼

🮌

│

π

◥

Ex

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

◤

🮇

├

▗

└

┐

▂

Fx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

🭿

▖

▝

┘

▘

π

Differs between PETSCII variants.

Shifted

[edit]

Shifted PETSCII

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x

1x

2x

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

3x

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

4x

@

a

b

c

d

e

f

g

h

i

j

k

l

m

n

o

5x

p

q

r

s

t

u

v

w

x

y

z

[

£

]

↑

←

6x

─

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

7x

P

Q

R

S

T

U

V

W

X

Y

Z

┼

🮌

│

🮕/🮖

🮘

8x

9x

Ax

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

🮙

🮇

├

▗

└

┐

▂

Bx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

✓

▖

▝

┘

▘

▚

Cx

─

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

Dx

P

Q

R

S

T

U

V

W

X

Y

Z

┼

🮌

│

🮕/🮖

🮘

Ex

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

🮙

🮇

├

▗

└

┐

▂

Fx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

✓

▖

▝

┘

▘

🮕/🮖

Differs between PETSCII variants.

1. ^ Jump up to:^{a b c} This is U+1FB95 CHECKER BOARD FILL on the VIC-20; and U+1FB96 INVERSE CHECKER BOARD FILL on the Commodore 64 and Commodore 128.

Commodore PET

[edit]

Unshifted

[edit]

Unshifted PETSCII (PET)

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x

1x

2x

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

3x

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

4x

@

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

5x

P

Q

R

S

T

U

V

W

X

Y

Z

[

\

]

↑

←

6x

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

7x

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

8x

9x

Ax

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

◤

🮇

├

▗

└

┐

▂

Bx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

🭿

▖

▝

┘

▘

▚

Cx

─

♠

🭲

🭸

🭷

🭶

🭺

🭱

🭴

╮

╰

╯

🭼

╲

╱

🭽

Dx

🭾

•

🭻

♥

🭰

╭

╳

○

♣

🭵

♦

┼

🮌

│

π

◥

Ex

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

◤

🮇

├

▗

└

┐

▂

Fx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

🭿

▖

▝

┘

▘

π

Differs from standard PETSCII.

Shifted

[edit]

Shifted PETSCII (PET)

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x

1x

2x

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

3x

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

4x

@

a

b

c

d

e

f

g

h

i

j

k

l

m

n

o

5x

p

q

r

s

t

u

v

w

x

y

z

[

\

]

↑

←

6x

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

7x

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

8x

9x

Ax

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

🮙

🮇

├

▗

└

┐

▂

Bx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

✓

▖

▝

┘

▘

▚

Cx

─

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

Dx

P

Q

R

S

T

U

V

W

X

Y

Z

┼

🮌

│

🮕

🮘

Ex

NBSP

▌

▄

▔

▁

▏

▒

▕

🮏

🮙

🮇

├

▗

└

┐

▂

Fx

┌

┴

┬

┤

▎

▍

🮈

🮂

🮃

▃

✓

▖

▝

┘

▘

🮕

Displayed case matches the Commodore PET 8032. The opposite case is used on the Commodore PET 2001.  Differs from standard PETSCII.

Control characters

[edit] While the graphic characters were mostly shared between Commodore systems, the control characters frequently varied. The follow table describes what the control characters represent on the Commodore PET 2001, Commodore PET 8032, VIC-20, Commodore 64, Commodore 16, Commodore 128 (40 and 80 column modes).

PETSCII control characters

Hex	Decimal	PET 2001	PET 8032	VIC-20	C64	C16	C128 (40 col)	C128 (80 col)
00	0	—
01	1	—
02	2	—						UNDERLINE ON
03	3	STOP
04	4	—
05	5	—		WHITE
06	6	—
07	7	—	BELL	—			BELL
08	8	—		LOCK CASE			—
09	9	—	TAB	UNLOCK CASE			TAB
0A	10	—					LINE FEED
0B	11	—					UNLOCK CASE
0C	12	—					LOCK CASE
0D	13	RETURN
0E	14	—	LOWER CASE
0F	15	—	SET WINDOW TOP	—				FLASH ON
10	16	—
11	17	CURSOR DOWN
12	18	REVERSE ON
13	19	HOME
14	20	DEL
15	21	—	KILL LINE	—
16	22	—	ERASE TO RIGHT	—
17	23	—
18	24	—			TAB SET/CLEAR
19	25	—	SCROLL UP	—
1A	26	—
1B	27	—	ESC	—		ESC
1C	28	—		RED
1D	29	CURSOR RIGHT
1E	30	—		GREEN
1F	31	—		BLUE
80	128	—
81	129	—			ORANGE			DARK PURPLE
82	130	—			FLASH ON	—	UNDERLINE OFF
83	131	—		RUN
84	132	—			FLASH OFF	—
85	133	—		F1
86	134	—		F3
87	135	—	DOUBLE BELL	F5
88	136	—		F7
89	137	—	TAB SET/CLEAR	F2
8A	138	—		F4
8B	139	—		F6
8C	140	—		F8		HELP	F8
8D	141	SHIFT + RETURN
8E	142	—	UPPER CASE
8F	143	—	SET WINDOW END	—				FLASH OFF
90	144	—		BLACK
91	145	CURSOR UP
92	146	REVERSE OFF
93	147	CLEAR
94	148	INST
95	149	—	INSERT LINE ABOVE	—	BROWN			DARK YELLOW
96	150	—	ERASE TO LEFT	—	PINK	YELLOW-GREEN	PINK
97	151	—			DARK GRAY	PINK	DARK GRAY	DARK CYAN
98	152	—			MEDIUM GRAY	BLUE-GREEN	MEDIUM GRAY
99	153	—	SCROLL DOWN	—	LIGHT GREEN	LIGHT BLUE	LIGHT GREEN
9A	154	—			LIGHT BLUE	DARK BLUE	LIGHT BLUE
9B	155	—			LIGHT GRAY	LIGHT GREEN	LIGHT GRAY
9C	156	—		PURPLE
9D	157	CURSOR LEFT
9E	158	—		YELLOW
9F	159	—		CYAN

The colors of the VIC-20 and C64/128 are listed in the VIC-II article.

Base 128

[edit]

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Out of PETSCII's first 192 codes, there are 128 graphic characters: 32–127 and 160–192. This permits "base128"-style encodings in DATA statements, or perhaps between PETSCII-speaking machines. This can also include control characters, which are visible when quoted, although which control characters are defined varies between systems.

The primary application for a "Base 128" encoding is in DATA statements in Commodore BASIC. Binary data can be stored with relatively low overhead, allowing one character of data to encode seven bits of data. On a standard 80-character line, typically four characters are used for the line number, and two characters for the tokenized DATA statement. Since the comma and colon are significant to BASIC, a quote character is also needed, leaving 73 characters for data. At seven bits per character, one DATA line could store 511 bits of binary data, for 79% efficiency. If three-digit line numbers are used, efficiency increases to 80%. If two-digit line numbers are used, efficiency is 82%.

Line Numbers	Data chars per Line	Bits per Line	Efficiency	Max. Lines	Max. Total Data Bytes
1-9	76	532	0.83125	9	598
10-99	75	525	0.820312	90	5,906
100-999	74	518	0.809375	900	58,275
1000-9999	73	511	0.7984375	9,000	574,875
10000-65535	72	504	0.7875	55,536	3.5 MB (approx.)

1. ^ Assume line 0 is a GOTO.
2. ^ Jump up to:^{a b} Maximum line number is probably off-by-one.

For storing binary data in Commodore BASIC, it appears that two- or three-digit line numbers are typically the best choice.

Base 164

[edit] 164 PETSCII characters are representable in quoted strings; theoretically, then, Base 164 is possible. This adds in the color values, the function keys, and cursor controls.

See also

[edit]

• ATASCII
• Atari ST character set
• ZX Spectrum character set
• Extended ASCII
• Text semigraphics

References

[edit]

1. ^
2. ^ Jump up to:^{a b}
3. ^
4. ^  (mirror)
5. ^
6. ^ Jump up to:^{a b c d e f g}
7. ^ Jump up to:^{a b c}
8. ^
9. ^
10. ^ Jump up to:^{a b}
11. ^
12. ^
13. ^
14. ^
15. ^
16. ^
17. ^

External links

[edit]

• PETSCII to Unicode mapping and a TrueType font using that mapping
• Typography in 8 bits: System fonts
• Online PETSCII-art editor
• PETSCII-art

v t e Character encodings
Early telecommunications	Telegraph code Needle Morse Non-Latin Wabun/Kana Chinese Cyrillic Baudot and Murray Fieldata ASCII ISO/IEC 646 BCDIC Teletex and Videotex/Teletext T.51/ISO/IEC 6937 ITU T.61 ITU T.101 World System Teletext background sets Transcode
ISO/IEC 8859	Approved parts -1 (Western Europe) -2 (Central Europe) -3 (Maltese/Esperanto) -4 (North Europe) -5 (Cyrillic) -6 (Arabic) -7 (Greek) -8 (Hebrew) -9 (Turkish) -10 (Nordic) -11 (Thai) -13 (Baltic) -14 (Celtic) -15 (New Western Europe) -16 (Romanian) Abandoned parts -12 (Devanagari) Proposed but not approved KOI-8 Cyrillic Sámi Adaptations Welsh Barents Cyrillic Estonian Ukrainian Cyrillic
Bibliographic use	MARC-8 ANSEL CCCII/EACC ISO 5426 5426-2 5427 5428 6438 6862
National standards	ArmSCII Big5 BraSCII CNS 11643 DIN 66003 ELOT 927 GOST 10859 GB 2312 GB 12345 GB 12052 GB 18030 HKSCS ISCII JIS X 0201 JIS X 0208 JIS X 0212 JIS X 0213 KOI-7 KPS 9566 KS X 1001 KS X 1002 LST 1564 LST 1590-4 PASCII Shift JIS SI 960 TIS-620 TSCII VISCII VSCII YUSCII
ISO/IEC 2022	ISO/IEC 8859 ISO/IEC 10367 Extended Unix Code / EUC
Mac OS Code pages ("scripts")	Armenian Arabic Barents Cyrillic Celtic Central European Croatian Cyrillic Devanagari Farsi (Persian) Font X (Kermit) Gaelic Georgian Greek Gujarati Gurmukhi Hebrew Iceland Inuit Keyboard Latin (Kermit) Maltese/Esperanto Ogham Roman Romanian Sámi Turkish Turkic Cyrillic Ukrainian VT100
DOS code pages	437 668 708 720 737 770 773 775 776 777 778 850 851 852 853 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 897 899 903 904 932 936 942 949 950 951 1034 1040 1042 1043 1044 1098 1115 1116 1117 1118 1127 3846 ABICOMP CS Indic CSX Indic CSX+ Indic CWI-2 Iran System Kamenický Mazovia MIK
IBM AIX code pages	895 896 912 915 921 922 1006 1008 1009 1010 1012 1013 1014 1015 1016 1017 1018 1019 1046 1124 1133
Windows code pages	CER-GS 932 936 (GBK) 950 1169 Extended Latin-8 1250 1251 1252 1253 1254 1255 1256 1257 1258 1270 Cyrillic + Finnish Cyrillic + French Cyrillic + German Polytonic Greek
EBCDIC code pages	Japanese language in EBCDIC DKOI
DEC terminals (VTx)	Multinational (MCS) National Replacement (NRCS) French Canadian Swiss Spanish United Kingdom Dutch Finnish French Norwegian and Danish Swedish Norwegian and Danish (alternative) 8-bit Greek 8-bit Turkish SI 960 Hebrew Special Graphics Technical (TCS)
Platform specific	1052 1053 1054 1055 1056 1057 1058 Acorn RISC OS Amstrad CPC Apple II ATASCII Atari ST BICS Casio calculators CDC Compucolor 8001 Compucolor II CP/M+ DEC RADIX 50 DEC MCS/NRCS DG International Galaksija GEM GSM 03.38 HP Roman HP FOCAL HP RPL SQUOZE LICS LMBCS MSX NEC APC NeXT PETSCII PostScript Standard PostScript Latin 1 SAM Coupé Sega SC-3000 Sharp calculators Sharp MZ Sinclair QL Teletext TI calculators TRS-80 Ventura International WISCII XCCS ZX80 ZX81 ZX Spectrum
Unicode / ISO/IEC 10646	UTF-1 UTF-7 UTF-8 UTF-16 UTF-32 UTF-EBCDIC GB 18030 DIN 91379 BOCU-1 CESU-8 SCSU TACE16 Comparison of Unicode encodings
TeX typesetting system	Cork LY1 OML OMS OT1
Miscellaneous code pages	ABICOMP ASMO 449 Digital encoding of APL symbols ISO-IR-68 ARIB STD-B24 Fieldata HZ IEC-P27-1 INIS 7-bit 8-bit ISO-IR-169 ISO 2033 KOI KOI8-R KOI8-RU KOI8-U Mojikyō SEASCII Stanford/ITS Symbol TRON Unified Hangul Code
Control character	Morse prosigns C0 and C1 control codes ISO/IEC 6429 JIS X 0211 Unicode control, format and separator characters Whitespace characters
Related topics	CCSID Character encodings in HTML Charset detection Han unification Hardware code page MICR code Mojibake Variable-length encoding
Character sets

Categories:

• Character sets
• Commodore International
• Commodore 64
• VIC-20
• ASCII
• Computer-related introductions in 1977