![]() This is done by the ANTIC chip.ĭue to this behavior, there is asymmetry in the selection of block-drawing characters. If the high-order bit is set on a character (i.e., if the byte value of the character is between 128 and 255), the character is generally rendered as the inverse video variant of its counterpart between 0 and 127, using a bitwise negation of the character's glyph. It does not flash.ĪTASCII only has 128 unique graphic characters, with the upper 128 graphic characters (index 128 to 255) being inverse video variants of the lower 128 graphic characters (index 0 to 127). ![]() The Atari screen editor implements the text cursor by simply inverting the character at the cursor position (by XOR with 0x80). ![]() This includes all uppercase letters and punctuation, but excludes lowercase letters and graphics characters. The 64 characters available in Modes 1 and 2 are the first 64 characters in the internal code, which correspond to ASTASCII codes 32 to 95 (0x20 to 0x5F). Mode 0 is the default graphics mode and supports 128 unique characters in one of two colors (regular or inverse video, depending on the upper bit) Modes 1 and 2 only support 64 unique characters, but support four different colors (as they use the upper two bits as color information instead). Mode 0 displays characters at the default size, Mode 1 displays them twice as wide (but the same height), and Mode 2 displays them twice as wide and twice the height. Modes 0, 1 and 2 represent pure text modes, while Modes 3 and above represent mixed or pure graphics modes (the exact number of distinct modes depending on the model). Ītari 8-bit systems have several distinct graphics modes these modes can be classified as pure text modes, pure graphics modes, or mixed modes. ATASCII codes are used by BASIC, while internal codes are used to look up how to render the character on-screen. ĪTASCII and internal codes contain the same character set, but indexed differently. When entering text, the Atari keyboard handler converts these signals into ATASCII. Due to there being two modifier keys, there are four distinct keyboard codes that can be sent by each character however, several keys (the exact keys depend on the model) do not send a control code if they are pressed while holding both Shift and Control. Pressing one of the two modifier keys ( Shift and Control) modifies the value input by pressing other keys. Keyboard codes represent the codes sent by the keyboard. Like most other variants of ASCII, ATASCII has its own distinct characters (arrows, blocks, box-drawing characters, playing card suits, etc.) in place of the C0 control codes in ASCII (characters 0–31), as well as replacing a few other ASCII code points.Ītari 8-bit systems have three distinct sets of codes: interchange codes (ATASCII), internal codes (also called screen codes), and keyboard codes. The Atari ST family of computers use the different Atari ST character set. The last computer to use the ATASCII character set is the Atari XEGS, which was released in 1987 and discontinued in 1992. The first computers in the Atari 8-bit family are the Atari 400 and 800, released in 1979, and later models were released throughout the 1980s. ATASCII is based on ASCII, but is not fully compatible with it. The ATASCII character set, from ATARI Standard Code for Information Interchange, alternatively ATARI ASCII, is a character encoding used in the Atari 8-bit family of home computers. Character encoding used by the Atari 8-bit family of home computers The entire visible ATASCII character set, both normal and inverse glyphs, upscaled to 2x to better show details
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