Propeller Manual

Introducing the Propeller Chip
Main ROM
The second half of Main Memory is all ROM. This space is used for character definitions,
math functions, and the Boot Loader and Spin Interpreter.
Character Definitions
The first half of ROM is dedicated to a set of 256 character definitions. Each character
definition is 16 pixels wide by 32 pixels tall. These character definitions can be used for
video displays, graphical LCD's, printing, etc. The character set is based on a North
American / Western European layout (Basic Latin and Latin-1 Supplement), with many
specialized characters inserted. The special characters are connecting waveform and
schematic building-blocks, Greek symbols commonly used in electronics, and several arrows
and bullets.
Figure 1-6: Propeller Font Characters
The character definitions are numbered 0 to 255 from left-to-right, top-to-bottom in Figure
1-6, above. In ROM, they are arranged with each pair of adjacent even-odd characters
merged together to form 32 longs. The first character pair is located in bytes $8000-$807F.
The second pair occupies bytes $8080-$80FF, and so on, until the last pair fills $BF80-
$BFFF. The Propeller Tool includes an interactive character chart (Help → View Character
Chart…) that has a ROM Bitmap view which shows where and how each character resides in
ROM.
Page 32 · Propeller Manual v1.1