User Rating 0.0 ★★★★★

Total Usage 0 times

Category Code Utilities

Input Format

ATASCII Values

Show control code placeholders Strip inverse video attribute Convert EOL (155) to newline

Converted ASCII Output

Byte-by-Byte Breakdown

#	ATASCII	Hex	ASCII	Description

Is this tool helpful?

Your feedback helps us improve.

★ ★ ★ ★ ★

About

ATASCII (Atari ASCII) is a proprietary character encoding used by the Atari 8-bit family of home computers (400, 800, XL, XE series). It maps 256 code points across the range 0 - 255, sharing partial overlap with standard ASCII in the printable range 32 - 122 but diverging significantly for control characters and the upper block. Misinterpreting ATASCII data as ASCII produces garbled output. Graphics characters (hearts, clubs, line-drawing segments) and inverse video codes (128 - 255) have no direct ASCII counterpart. This tool performs a best-effort mapping: shared printable characters pass through unchanged, Atari-specific control codes are transliterated to descriptive placeholders, and inverse video characters are mapped to their base glyph equivalent. The conversion is lossy by nature - ATASCII graphics glyphs cannot be faithfully represented in 7-bit ASCII.

Input accepts comma-separated or space-separated decimal values, hexadecimal strings (prefixed with 0x or bare hex pairs), or raw Atari binary files via upload. The tool approximates visual equivalents assuming standard ATASCII as documented in the Atari 400/800 Operating System Reference Manual (1982). Note: ATASCII variants used by Atari ST or Atari 2600 are not covered.

Formulas

ATASCII to ASCII conversion uses a direct lookup function f(c) where c is the ATASCII byte value:

{

map[c] if c ∈ {0 - 31, 123 - 127}chr(c) if 32 ≤ c ≤ 122f(c − 128) if 128 ≤ c ≤ 255

Where c = input ATASCII byte value (0 - 255), map[c] = predefined lookup for non-printable or Atari-specific codes, chr(c) = direct character cast (shared range), and codes 128 - 255 are inverse video variants resolved by subtracting 128 and re-applying the function recursively. Special case: ATASCII 155 (0x9B) maps to newline (LF, ASCII 10) as it is the Atari End-of-Line marker.

Reference Data

ATASCII Code	Hex	ATASCII Glyph	ASCII Equivalent	Notes
0	00	♥	♥	Heart (no ASCII equiv.)
1	01	├	\|	Box drawing right tee
2	02	▐	\|	Right half block
3	03	┘	+	Box drawing corner
4	04	┤	\|	Box drawing left tee
5	05	┐	+	Box drawing corner
6	06	╱	/	Diagonal line
7	07	╲	\	Reverse diagonal
8	08	◢	/	Triangle lower right
9	09	▗	.	Quadrant lower right
10	0A	◣	\	Triangle lower left
11	0B	▝	.	Quadrant upper right
12	0C	▘	.	Quadrant upper left
13	0D	▀	=	Upper half block
14	0E	▂	_	Lower quarter block
15	0F	▖	.	Quadrant lower left
16	10	♣	♣	Club
17	11	┌	+	Box drawing corner
18	12	─	-	Horizontal line
19	13	┼	+	Box drawing cross
20	14	●	*	Filled circle
21	15	▄	_	Lower half block
22	16	▎	\|	Left quarter block
23	17	┬	+	Box drawing tee down
24	18	┴	+	Box drawing tee up
25	19	▌	\|	Left half block
26	1A	└	+	Box drawing corner
27	1B	ESC	[ESC]	Escape
28	1C	↑	^	Cursor up
29	1D	↓	v	Cursor down
30	1E	←	<	Cursor left
31	1F	→	>	Cursor right
32 - 122	20 - 7A	(Standard printable)	Same	Direct ASCII overlap
123	7B	♠	♠	Spade (replaces {)
124	7C	\|	\|	Pipe (same)
125	7D	CLR	[CLR]	Clear screen
126	7E	BS	[BS]	Backspace
127	7F	TAB	[TAB]	Tab character
128 - 255	80 - FF	(Inverse video)	code − 128	Inverse of codes 0-127
155	9B	EOL	\n	Atari End-of-Line (newline)

Frequently Asked Questions

Atari repurposed the standard ASCII control character range (0-31) to display graphical glyphs: hearts, clubs, box-drawing segments, and block elements. These characters were rendered on screen rather than triggering terminal control functions. ASCII uses the same range for non-printable control codes (NUL, SOH, STX, etc.). This converter maps each ATASCII graphic glyph to the closest visual ASCII approximation - for example, ATASCII code 18 (horizontal line ─) maps to the hyphen-minus character.

ATASCII codes 128-255 are inverse video (reversed foreground/background) versions of codes 0-127. The converter strips the inverse attribute by subtracting 128 from the code, then converts the resulting base character normally. Inverse video is a display attribute with no ASCII representation, so this information is necessarily lost during conversion.

ATASCII 155 is the Atari End-of-Line (EOL) marker. It functions identically to a newline in ASCII text. Atari does not use ASCII 10 (LF) or 13 (CR) for line breaks. If you convert an Atari text file and ignore code 155, all lines will merge into a single string. This converter maps 155 to ASCII newline (LF, code 10) automatically.

Only approximately. ATASCII includes 29 unique graphic characters (block elements, diagonals, playing card suits) that have no direct ASCII equivalent. The converter substitutes the closest visual match: vertical blocks become pipe characters, diagonal fills become slashes, and corner pieces become plus signs. For faithful rendering, use an Atari emulator or a Unicode-capable viewer with ATASCII font mapping.

No. Atari BASIC saves programs in a tokenized binary format where byte values represent BASIC keywords, not ATASCII characters. Converting a tokenized BASIC file through this tool will produce meaningless output. This converter is designed for plain ATASCII text files, such as those created by the Atari screen editor or saved with PUT/PRINT statements in untokenized mode.

ATASCII replaces ASCII codes 123 ({) and 125 (}) with a spade glyph (♠) and a Clear Screen control code, respectively. Code 124 (|) is the same in both encodings. This means Atari programs that output these codes will show card suit symbols or trigger screen operations instead of producing curly braces. The converter maps code 123 to the spade Unicode character and code 125 to the placeholder [CLR].