Talk:Apple II character set

This page contains no references. 80.5.237.92 (talk) 20:28, 31 August 2017 (UTC)[reply]

This page currently has some issues. In terms of what the hardware displayed on a classic II, take a look at Table 7 (page 15), "ASCII Screen Characters", in the original Apple II Reference Manual (scans available, e.g. http://www.classiccmp.org/cini/pdf/Apple/Apple%20II%20Reference%20Manual%20-%20Woz.pdf). Quick summary:

00-1f: ASCII 40-5f, but inverse text
20-3f: ASCII 20-3f, but inverse text
40-5f: ASCII 40-5f, but flashing text
60-7f: ASCII 20-3f, but flashing text
80-9f: ASCII 40-5f (officially control characters, but displayed as normal text)
a0-bf: ASCII 20-3f
c0-df: ASCII 40-5f
e0-ff: ASCII 20-3f (Apple ][/][+) -or- ASCII 60-7f (Apple //e and later systems with lower case)

The basic difference between the hardware encoding and ASCII is that the high bit is set for "normal" behavior. A bitwise AND of the "high-ASCII" value with 0x3f or 0x7f gets you inverse or flashing text, respectively.

Early Apple IIs didn't support lower case, but later ones did. Only "normal" text could be lower case; inverse and flashing modes would map e0-ff to 20-3f or 60-7f, giving you what looked like inverse or flashing line noise.

In 80-column mode (//e and later), the output is similar but replaces flashing upper-case text with inverse and gains lower case:

40-5f: ASCII 40-5f, inverse
60-7f: ASCII 60-7f, inverse

Starting with the Apple //c, an alternate character set with MouseText (https://en.wikipedia.org/wiki/MouseText) could be enabled. It left the character set largely unchanged, but replaced flashing upper-case text in the character map:

40-5f: MouseText

The Apple IIgs worked the same as the Apple //e in 8-bit mode. When using the super hi-res screen, the system used the same Mac OS Roman character set (https://en.wikipedia.org/wiki/Mac_OS_Roman) that the Mac did. (You can see an image of 16-point Courier in the Teach Text app on a IIgs here: https://faddensoft.com/chartest/gs-charset-cour.png .)

There are some additional issues with the glyphs, e.g the Apple //e and IIgs have different glyphs for two of the MouseText characters. Some discussion can be found in this thread: https://groups.google.com/forum/#!topic/comp.sys.apple2/wuVAOLsrC9o

Fadden0 (talk) 16:10, 9 August 2018 (UTC)[reply]