PETSCII Character Chart

PETSCII (PET Standard Code of Information Interchange) is the Commodore 64’s character encoding system — Commodore’s own manuals call it “CBM ASCII” or “PET ASCII”. Unlike ASCII, PETSCII includes built-in graphics characters, colour control codes, and cursor movement—everything needed for games and demos. But here’s the catch: PETSCII codes and screen codes are different numbers for the same character.

When you PRINT "A" or use CHR$(65), you’re using PETSCII. When you POKE 1024,1, you’re using screen codes. Same letter ‘A’, different numbers (65 vs 1). Master this distinction and you’ve unlocked direct hardware control.

A 16 by 16 grid of every C64 screen code, drawn on a Commodore 64 screen, with hexadecimal row and column labels 0 to F along the top and left. — All 256 screen codes, drawn by the machine itself. Read the row as the high nibble and the column as the low nibble: the cell at row 4, column 1 is code $41 — decimal 65 — which is a spade, not the letter A. That is the whole distinction in one picture, since PETSCII 65 is the letter.

The chart above is the screen-code set — the numbers you POKE. Row 0 begins @ABCDEFG…, so the letter A is screen code 1. In PETSCII, which is what PRINT and CHR$ use, the letter A is 65 — and screen code 65 is something else entirely.

The Critical Difference

PETSCII Codes

Used with:

PRINT "HELLO"
CHR$(147) — clear screen
ASC("A") — returns 65
GET A$ — keyboard input
INPUT statements

Screen Codes

Used with:

POKE 1024,1 — write directly to screen memory
PEEK(1024) — read screen memory
Assembly: STA $0400 (direct screen writes)

Quick example:

PRINT "A"       : REM Uses PETSCII 65
POKE 1024,1     : REM Uses screen code 1
REM Both display the letter A!

Memory Locations

Memory	Address	Decimal	What It Does
Screen RAM	$0400-$07E7	1024-2023	Character positions (40×25)
Colour RAM	$D800-$DBE7	55296-56295	Colour for each character

Formula for any position:

Position = 1024 + (row * 40) + column
Colour = 55296 + (row * 40) + column

Row 0 is the top, column 0 is the left. Position (0,0) is address 1024.

Common Characters (Uppercase Mode)

Character	PETSCII	Screen Code	Notes
Space	32	32	Same in both
0-9	48-57	48-57	Same in both
@	64	0	Different!
A	65	1	Different!
B	66	2	Different!
C	67	3	Different!
…	…	…	…
Z	90	26	Different!
[	91	27	Different
£	92	28	Pound sterling
]	93	29	Different
↑	94	30	Up arrow
←	95	31	Left arrow

Pattern: For letters A-Z, subtract 64 from PETSCII to get screen code.

Control Characters

These codes don’t display—they do things. Essential for clearing screens, moving cursors, and changing colours.

Code	CHR$()	What It Does
13	CHR$(13)	Carriage return (ENTER key)
19	CHR$(19)	Home cursor (top-left)
147	CHR$(147)	Clear screen (most used!)
17	CHR$(17)	Cursor down one line
145	CHR$(145)	Cursor up one line
29	CHR$(29)	Cursor right one space
157	CHR$(157)	Cursor left one space
18	CHR$(18)	Reverse video on
146	CHR$(146)	Reverse video off
14	CHR$(14)	Switch to lowercase/mixed-case charset
142	CHR$(142)	Switch to uppercase/graphics charset

Switching charsets is implemented by changing the VIC-II’s character base pointer ($D018 bits 1-3) — CHR$(14) points at the lowercase character ROM region, CHR$(142) at the uppercase/graphics region. Both ROM regions live inside the C64’s character ROM at $D000-$DFFF; the switch is just a register write, instantaneous.

Game use: CHR$(147) clears the screen instantly. CHR$(19) resets cursor to home. Both faster than scrolling or manually clearing.

Colour Control Codes

Change text colour mid-PRINT with these PETSCII codes:

Colour	PETSCII	Example
Black	144	`PRINT CHR$(144);`
White	5	`PRINT CHR$(5);`
Red	28	`PRINT CHR$(28);`
Cyan	159	`PRINT CHR$(159);`
Purple	156	`PRINT CHR$(156);`
Green	30	`PRINT CHR$(30);`
Blue	31	`PRINT CHR$(31);`
Yellow	158	`PRINT CHR$(158);`
Orange	129	`PRINT CHR$(129);`
Brown	149	`PRINT CHR$(149);`
Light Red	150	`PRINT CHR$(150);`
Dark Grey	151	`PRINT CHR$(151);`
Grey	152	`PRINT CHR$(152);`
Light Green	153	`PRINT CHR$(153);`
Light Blue	154	`PRINT CHR$(154);`
Light Grey	155	`PRINT CHR$(155);`

Example:

PRINT CHR$(147);CHR$(31);"SCORE: ";CHR$(158);"9999"

Clear screen, blue “SCORE:”, yellow number—all in one line.

Colour RAM Values (For POKEing)

When writing directly to colour RAM (55296+), use these values:

Colour	Value	Hex
Black	0	$00
White	1	$01
Red	2	$02
Cyan	3	$03
Purple	4	$04
Green	5	$05
Blue	6	$06
Yellow	7	$07
Orange	8	$08
Brown	9	$09
Light Red	10	$0A
Dark Grey	11	$0B
Grey	12	$0C
Light Green	13	$0D
Light Blue	14	$0E
Light Grey	15	$0F

Note: Only the low 4 bits matter—POKE 55296,18 gives you red (18 AND 15 = 2).

Graphics Characters

PETSCII includes built-in line-drawing and symbol characters, perfect for game borders and UI:

Description	PETSCII	Screen Code
Horizontal line ─	99	67
Vertical line │	98	66
Upper-left corner ╭	117	85
Upper-right corner ╮	105	73
Lower-left corner ╰	106	74
Lower-right corner ╯	107	75
Cross ┼	110	78
Heart ♥	115	83
Diamond ♦	122	90
Club ♣	120	88
Spade ♠	97	65
Circle ●	113	81
Solid block █	160	96

Every one of these sits on a shifted letter key, and each row was read back from screen RAM after printing the code rather than derived — PRINT CHR$(97) then PEEK(1024) returns 65.

The 193–218 range prints the same characters. CHR$(193) and CHR$(97) both put screen code 65 on the screen, so either works and you will see both in listings.

Game use: Draw UI borders with line characters. Hearts for lives. Solid blocks for platforms or walls.

Conversion Rules

PETSCII → Screen Code

Letters A-Z (uppercase):

Screen = PETSCII - 64
Example: 'A' = 65 - 64 = 1

Numbers and symbols (32-63):

Screen = PETSCII (same)
Example: '0' = 48 (both)

Graphics/shifted (97-122):

Screen = PETSCII - 32
Example: spade = 97 - 32 = 65

Measured across every graphics character in the table above, and it holds for all of them. The equivalent codes in the 193-218 range print the same characters.

Screen Code → PETSCII

Quick approximation:

IF S<32 THEN P=S+64
IF S>=32 AND S<64 THEN P=S
IF S>=64 THEN P=S+64

Better: Use lookup tables for accuracy.

Practical Examples

Example 1: Clear Screen and Set Colours

10 PRINT CHR$(147);
20 PRINT CHR$(31);
30 PRINT CHR$(18);
40 PRINT "  GAME OVER  ";
50 PRINT CHR$(146)

Example 2: Draw a Simple Box

10 PRINT CHR$(147);CHR$(5)
20 PRINT CHR$(85);
30 FOR I=1 TO 18
40 PRINT CHR$(67);
50 NEXT I
60 PRINT CHR$(73)

Example 3: Write Text Directly to Screen

10 REM Display "HI" at position (5,10)
20 P=1024+(5*40)+10
30 POKE P,8
40 POKE P+1,9
50 C=55296+(5*40)+10
60 POKE C,7
70 POKE C+1,7

Example 4: Scroll Text Effect

10 T$="*** WELCOME TO THE GAME ***"
20 FOR I=1 TO LEN(T$)
30 PRINT CHR$(19);
40 PRINT MID$(T$,I,40)
50 FOR D=1 TO 50:NEXT D
60 NEXT I
70 GOTO 20

Two appendices, two tables

The Programmer’s Reference Guide keeps the two numberings in separate appendices and never blurs them. Appendix B, “Screen Display Codes”, “shows which numbers should be POKEd into screen memory (locations 1024 – 2023) to get a desired character”, adds that “the reverse character code may be obtained by adding 128”, and gives the two case-switching POKEs — POKE 53272,21 for upper case and graphics, POKE 53272,23 for lower case. Appendix C, “ASCII and CHR$ Codes”, covers the other table: “what characters will appear if you PRINT CHR$(X), for all possible values of X”, and what ASC returns — which the manual recommends “in evaluating the character received in a GET statement, converting upper/lower case, and printing character based commands (like switch to upper/lower case) that could not be enclosed in quotes”.

Every character code the C64 knows about