Character Generation - Zenith Data Systems Z-100 Series Installation Manual

Page
3.3
General Theory of Operation
Character Generation
An alphanumeric character is generated by a matrix of pixels located inside
a 9 x 14 field of pixels. Unused columns and rows provide spacing be-
tween the characters. Figure 3.1 shows the organization of the standard
numeric character 7. The addresses are shown to indicate the bytes re-
quired to generate the number.
The character ROM generates the pixel lighting data based on the charac-
ter stored in RAM and the address from the CRTC. Different fonts are
possible by changing the character ROM. A second unsupported font may
be contained on the standard ROM; this font may be addressed by chang-
ing bits 6 and 7 of the control register.
1 4 - - - - - - 720 DOTS
- - - - - - - - - - + 1 __ 1
oe================~~
~+------------------
3+- _
- - - - - - - - - - - - - - - - j
1
CHARACTER
(9 DOTS)
~
012345678
~ttmlW
1 14
~tttlt~
f - - - - - - - - - - - - - - - - - C H A R A C T E R
=
SCAN
f - - - - - - l f - - - - - - - - - - ' C
..1----
350
HORIZONTAL
SCAN LINES
Figure
3.1.
Character Generation