Sinclair ZX80 character set

The Sinclair ZX80 character set rendered in the system font.
Language	English withpseudographics
Created by	Sinclair Research
Succeeded by	ZX81 character set
Other related encoding	ZX Spectrum character set

TheZX80 character set is thecharacter encoding used by theSinclair ResearchZX80microcomputer with its original 4KBASICROM. The encoding uses onebyte per character for 256 code points. It has no relationship with previously established ones likeASCII orEBCDIC, but it is related though not identical to thecharacter set of the successor ZX81.

The character set has 64 unique glyphs present at code points 0–63. With themost significant bit set the character is generated ininverse video; corresponding to code points 128–191. These 128 values are the only displayable ones allowed in the video memory (known as the display file). The remaining code points (64–127 and 192–255) are used as control characters orSinclair BASIC keywords, while some are unused.

The small effective range of only 64 unique glyphs has led to the exclusion of many characters, includingLatinlower case letters and symbols used widely in computing such as theexclamation mark and theat sign.

There are 11block graphics characters, counting code point 0 which also doubles as space. Together with the 11 inverse video versions these 22 code points provide every combination of the character cell divided into 2×2 black-and-white block pixels for low-resolution 64×48 pixel graphics, or into 1×2 black, white ordithered gray wide block pixels for a 32×48 resolution. The 2×2 versions of these are also present in theBlock ElementsUnicode block.

Code point 1 is the double-quote" character when used in the display file, but uniquely to the ZX80 it is used internally as thestring terminator character^[1] so the BASIC functionCHR$(1) returns a null string;^[2]CHR$(212) translates to the printable " character.^[3]

The 8K BASICROM of the follow-upZX81 model was also available as an upgrade for the ZX80, replacing its integer-only 4K BASIC ROM.^[4] It introduced the modifiedZX81 character set which has mostly the same code points, e.g. for A-Z and 0-9, but the code points are different for the block graphics characters, the symbols ", -, +, *, /, =, >, <, and the BASIC keyword tokens (with many new added). There are also changes to the control characters and code point 1 is no longer an unprintable string terminator.

In the laterZX Spectrum the entire character encoding was replaced with theZX Spectrum character set, which is a derivative of ASCII and includes lower case letters and more.

The ZX80 system font uses an 8×8 pixel-per-character grid where most glyphs fit in 7×6 pixels leaving one pixel horizontal space between them. This font was modified in the ZX81's ROM to slightly narrower 6×6 pixel glyphs with two pixels horizontal space between them, which improved the look of singleinverted characters by showing inverted pixels on both sides. Some glyphs also received a different design in the ZX81 system font, noticeable on the *, the slashed and less rounded 0, and the less rounded $, C, G and J.

The following table shows the ZX80 character set. Each character is shown with a potentialUnicode equivalent. Space and control characters are represented by the abbreviations for their names.

ZX80 character set^[1][3][a]

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x

SP

"[b]

[c]

£

$

:

?

1x

(

)

-

+

*

/

=

>

<

;

,

.

0

1

2

3

2x

4

5

6

7

8

9

A

B

C

D

E

F

G

H

I

J

3x

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

4x

5x

6x

7x

UP

DOWN

LEFT

RIGHT

HOME

EDIT

NEL

RUBOUT

8x

"

[c]

£

$

:

?

9x

(

)

-

+

*

/

=

>

<

;

,

.

0

1

2

3

Ax

4

5

6

7

8

9

A

B

C

D

E

F

G

H

I

J

Bx

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Cx

Dx

"[b]

THEN

TO

;

,

)

(

NOT

-

+

*

/

Ex

AND

OR

**[d]

=

>[a]

<[a]

LIST

RETURN

CLS

DIM

SAVE

FOR

GO TO

POKE

INPUT

RANDOMISE

Fx

LET

NEXT

PRINT

NEW

RUN

STOP

CONTINUE

IF

GO SUB

LOAD

CLEAR

REM

• ZX81 character set
• ZX Spectrum character set
• Sinclair QL character set
• ATASCII
• Atari ST character set
• PETSCII
• Extended ASCII

• Character sets
• ZX80

• Articles with short description
• Short description matches Wikidata