PETSCII (PET Standard Code of Information Interchange), also known as CBM ASCII, is the variation of the ASCII character set used in Commodore (CBM)'s 8-bit home computers, starting with the PET from 1977 and including the VIC-20, C64, Plus/4, C16 and C128.* There are 95 printable ASCII characters, numbered 32 to 126. ... Commodore is the commonly used name for Commodore International, an electronics company who was a major player in the 1980s home computer field. ... The home computer is a consumer-friendly word for the second generation of microcomputers (the technical term that was previously used), entering the market in 1977 and becoming common during the 1980s. ... The PET (Personal Electronic Transactor) was a home-/personal computer produced by Commodore starting in the late 1970s. ... VIC-20 with accessories. ... Close-up of C64 Commodore 64 (C64, CBM 64) was a popular home computer of the 1980s. ... The Commodore Plus/4 was a home computer released by Commodore International in 1984 and intended to replace the Commodore 64 as its flagship computer. ... The Commodore 16 was a home computer made by Commodore with a 6502-compatible 7501 CPU, released in 1984. ... The Commodore 128 is a home/personal computer, also known as the C128. ...

C64 startup screen with shifted and unshifted modes of PETSCII, and the two characters from ASCII-1963.

PETSCII is based on the 1963 version of ASCII (rather than the 1967 version, of which all modern character sets are supersets). As such, PETSCII has only uppercase letters (in its unshifted mode, that is; see below), an up-arrow (↑) instead of a caret (^) in position $5E and a left-arrow (←) instead of an underscore ( _ ) in position $5F. In unshifted mode, codes $60–$7F and $A0–$FF are allotted to CBM-specific block graphics characters (horizontal and vertical lines, hatches, shades, triangles, circles and card suites). Ranges $00–$1F and $80–$9F have control codes. The characters in positions $60–$7F repeat themselves in positions $C0–$DF, as do $A0–$BE in $E0–$FE. Shifted and unshifted modes of PETSCII on the C64. ... In mathematics, hexadecimal or simply hex is a numeral system with a radix or base of 16 usually written using the symbols 0–9 and A–F or a–f. ... Some typical modern playing cards. ...

The Commodore PET's lack of a programmable bitmap-mode for computer graphics as well as it having no redefinable character set capability, may be one of the reasons PETSCII was developed; by creatively using the well thought-out block graphics, a higher degree of sophistication in screen graphics is attainable than by using plain ASCII's letter/digit/punctuation characters. In addition to the relatively diverse set of geometrical shapes that can thus be produced, PETSCII allows for several grayscale levels by its provision of differently hatched checkerboard squares/half-squares. Finally, the reverse-video mode (see below) is used to complete the range of graphics characters, in that it provides mirrored half-square blocks. The PET (Personal Electronic Transactor) was a home-/personal computer produced by Commodore starting in the late 1970s. ... Suppose the smiley face in the top left corner is an RGB bitmap image. ... 2D computer graphics is the computer-based generation of digital images—mostly from two-dimensional models (such as 2D geometric models, text, and digital images) and by techniques specific to them. ... In computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample. ... A checkerboard is a board on which checkers is played. ...

PETSCII also has a shifted mode, in which the range $41–$5A has lowercase letters (instead of uppercase in unshifted mode), and the range $61–$7A (and its duplicate $C1–$DA) has uppercase letters (instead of the block graphics). This is in reverse to ASCII-1967, so any text transfer between an 8-bit Commodore machine and one that uses standard ASCII would result in reverse-case text upon arrival to the destination. Thus, like for other computers based on non-standard-ASCII character sets, software conversion is needed when exchanging text files and/or telecommunicating with standard ASCII systems. The other ranges are unchanged in shifted mode.

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, like the above examples. The screen control codes were essentially similar to escape codes for text based computer terminals. A cursor is a movable marker that indicates a position. ... To prettyprint (or pretty-print) is to make something, commonly some printed material, appear more appealing to the human eye. ... An escape sequence is a series of characters used to trigger some sort of command state in computers and their attached peripherals. ...

As indicated above, PETSCII provides for shifting between the power-on default (unshifted) uppercase+graphics character set and the alternative (shifted) lower+uppercase set (where the shifted set contains a subset of the block graphic characters of the unshifted set). The shift between modes is done via special control codes. Thus, screen editor state changes, rather than the employment of separate ASCII codes, are used to choose between single-case (all capitals) and dual case. In the VIC-20, C64, and later machines (not including the CBM business computers), color codes supplement the other screen control codes. (The colors of the VIC-20 and C64/128 are listed in the C64 article.)

Mapping PETSCII to Unicode is impossible, since not all PETSCII graphics characters are encoded in Unicode. Unmappable characters should be replaced by the Unicode replacement character, U+FFFD (�), or mapped to the private-use range of Unicode. In computing, Unicode is the international standard whose goal is to provide the means to encode the text of every document people want to store in computers. ...

• ) The Amiga computers use standard ASCII.
  

See also: ATASCII, Spectrum Character Set Amiga is the name of a range of home/personal computers primarily using the Motorola 68000 processor family, whose development started in 1982, initially as a game machine. ... The ATASCII character set, from ATARI Standard Code for Information Interchange, alternatively ATARI ASCII, is the variation on ASCII used in the Atari 8-bit family of home computers, starting with the 1979 Atari 400/800 and going all the way to the XEGS. Like most other non-standard ASCIIs... The ZX Spectrum character set is the variant of ASCII used in the British Sinclair Spectrum computers. ...

External links

• PETSCII character map, part 1 (http://www.df.lth.se/~triad/krad/recode/pet1.jpg), part 2 (http://www.df.lth.se/~triad/krad/recode/pet2.jpg), part 3 (http://www.df.lth.se/~triad/krad/recode/pet3.jpg) (JPEG)
• an attempt at PETSCII to Unicode mapping, unshifted (http://www.df.lth.se/~triad/krad/recode/petscii_c64en_uc.txt), shifted (http://www.df.lth.se/~triad/krad/recode/petscii_c64en_lc.txt)