Jump to content

Amstrad CPC character set

From Wikipedia, the free encyclopedia

This is the current revision of this page, as edited by RetroEditor (talk | contribs) at 17:29, 15 April 2024 (Added new information about the symbols for legacy computing supplement.). The present address (URL) is a permanent link to this version.

(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)

The Amstrad CPC character set (alternatively known as the BASIC graphics character set)[1] is the character set used in the Amstrad CPC series of 8-bit personal computers when running BASIC (the default mode, until it boots into CP/M). This character set existed in the built-in "lower" ROM chip. It is based on ASCII-1967, with the exception of character 0x5E which is the up arrow instead of the circumflex, as it is in ASCII-1963, a feature shared with other character sets of the time.[2][3] Apart from the standard printable ASCII range (0x20-0x7e), it is completely different from the Amstrad CP/M Plus character set. The BASIC character set had symbols of particular use in games and home computing, while the CP/M Plus character reflected the International and Business flavor of the CP/M Plus environment.[4] This character set is represented in Unicode (excluding 0xEF, 0xFC, and 0xFD)[5] as of the March 2020 release of Unicode 13.0, which added symbols for legacy computing. The three missing characters have however been accepted for inclusion in Unicode 16.0 in the symbols for legacy computing supplement.[6]

Character set

[edit]
Amstrad CPC[7][8][9][a]
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 { | } ~ DEL
8x  
9x ·
Ax ^ ´ ¨ £ © § ¼ ½ ¾ ± ÷ ¬ ¿ ¡
Bx α β γ δ ε θ λ μ π σ φ ψ χ ω Σ Ω
Cx 🮠 🮡 🮣 🮢 🮧 🮥 🮦 🮤 🮨 🮩 🮮 🮕
Dx 🮎 🮍 🮏 🮌 🮜 🮝 🮞 🮟
Ex
Fx 🯆 🯅 🯇 🯈
  No Unicode mapping[5]
  1. ^ The control characters normally do not produce a character on screen, but are interpreted as control codes. When using the character 1 (SOH) as a prefix, or with the graphics text, or entered from the keyboard, they are displayed with the representation on the bottom of the cell.[10]

Control characters

[edit]

Each of the characters in the C0 character range (0x00-0x1F) had a special function.[11]


BASIC Control characters
Value (hex) Value(dec) Name Parameter Locomotive BASIC equivalent Function
00 0 NUL No effect. Ignored.
01 1 SOH 0-255 Print the symbol given by the parameter value. This allows the symbols in the range 0 to 31 to be displayed.
02 2 STX CURSOR 0 Turn off text cursor.
03 3 ETX CURSOR 1 Turn on text cursor.
04 4 EOT 0-2 MODE Set screen mode.
05 5 ENQ 0-255 Send the parameter character to the graphics cursor.
06 6 ACK Enable Text Screen (see NAK)
07 7 BEL Sound Bleeper. Note that this flushes the sound queues.
08 8 BS Move cursor back one character.[a]
09 9 TAB Move cursor forward one character.[a]
0A 10 LF Move cursor down one line.[a]
0B 11 VT Move cursor up one line.[a]
0C 12 FF CLS Clear text window and move cursor to top left corner.
0D 13 CR Move cursor to left edge of window on current line.[a]
0E 14 SO 0-15 PAPER Set Paper Ink.
0F 15 SI 0-15 PEN Set Pen Ink.
10 16 DLE Delete current character.[a]
11 17 DC1 Clear from left edge of window to, and including, the current character position.[a]
12 18 DC2 Clear from, and including, the current character position to the right edge of window.[a]
13 19 DC3 Clear from start of window to, and including, the current character position.[a]
14 20 DC4 Clear from, and including, the current character position to the end of window.[a]
15 21 NAK Turn off text screen. The screen will not react to anything sent to it until after an ACK is sent.
16 22 SYN 0-1 Set transparency (0 disables, 1 enables)
17 23 ETB 0-3 Set graphics ink mode. 0 normal (overwrite), 1 XOR, 2 AND, 3 OR
18 24 CAN Exchange Pen and Paper Inks, effectively applying the reverse video effect.
19 25 EM 0-255 (9 times) SYMBOL Set the matrix for user definable character. The first parameter specifies which character's matrix to set. The next eight specify the matrix.
1A 26 SUB 1-80, 1-80, 1-25, 1-25 WINDOW Set Window. The parameters specify left, right, top and bottom edges of the window.
1B 27 ESC No effect. Ignored.
1C 28 FS 0-15, 0-31, 0-31 INK Set Ink to a pair of colors. The first parameter specifies the Ink, the next two the required colors. [b]
1D 29 GS 0-31, 0-31 BORDER Set Border to a pair of colors. Equivalent to a BORDER command. The two parameters specify the two colors.[b]
1E 30 RS Move cursor to top left hand corner of window.
1F 31 US 1-80, 1-25 LOCATE Move cursor to the given position in the current window. The first parameter gives the column to move to, the second gives the line.
  1. ^ a b c d e f g h i j The codes marked force the cursor to a legal position in the current window before they are obeyed - but may leave the cursor in an illegal position

References

[edit]
  1. ^ "Chapter 7: For your reference ...." (PDF), Amstrad CPC 6128 User Instructions, 1985, p. 9
  2. ^ ZX Spectrum character set
  3. ^ PETSCII
  4. ^ "Chapter 7: For your reference ...." (PDF), Amstrad CPC 6128 User Instructions, 1985, p. 54
  5. ^ a b "Character Not Proposed" (PDF), L2/19-025: Sources, 2019-01-04
  6. ^ "Symbols for Legacy Computing Supplement" (PDF).
  7. ^ "AMSCPC.TXT" (PDF), L2/19-025: Proposal to add characters from legacy computers and teletext to the UCS, 2019-01-04
  8. ^ L2/19-025: Sources (PDF), 2019-01-04
  9. ^ "Chapter 7: For your reference ...." (PDF), Amstrad CPC 6128 User Instructions, 1985, pp. 9–20
  10. ^ Godden, Bruce; Overell, Paul; Radisic, David (1986), "Appendix VI: Displayed Character Set", CPC 464/664/6128 FIRMWARE, Amstrad Consumer Electronics, p. 431
  11. ^ "Chapter 7: For your reference ...." (PDF), Amstrad CPC 6128 User Instructions, 1985, pp. 3–6