Zenith Data Systems Z-100 Series Installation Manual page 38

Page
3.8
General Theory of Operation
NOTE: The illustrations on this page depict typical operation and not the
actual display from the Z-329 Card.
- - EVEN NUMBER FIELD (FIRST)
- - - - ODD NUMBER FIELD (SECOND)
VERTICAL
SCAN
PERIOD
VERTICAL
L -
.:::=::::::.0..1
------+--+-
RE TRAC E
I ~
PERIOD
~HORIZONTAL
SCAN RETRACE
PERIOD PERIOD
ACTIVE
DISPLAY
NON-INTERLACE
MODE
SCAN
LINE
ADDRESS
o
_~
-()--1
:-S-oo-ot--
3
- -e- - - -
-8:
-5
6
0 0
--e-----~--l
0 - - - - - - -
----------1
2 - - - - - - -
- - - - - - - - - 3
4 - - - - - - -
---------·5
6 - - - - - - -
---------7
EVEN ODD
FIELD FIELD
INTERLACE
PLUS VIDEO
MODE
SCAN
LINE
ADDRESS
0 - - - - - - -
---------·0
1
~ 0
2
--g- -- --
Z--1
--e-----o--2
3
<Y
0
-~----_e-3
:-8z:g:~t--4
6
-!-----<r-
5
7
-~----=f-6
--e-----e--7
EVEN ODD
FIELD FIELD
INTERLACE
MODE
o
o
o
o
o
o
o
0
4
0 0 0
2
0
3
0
5
0
6
0
7
0
SCAN
LINE
ADDRESS
0 - - - - - -
1
0
Figure 3.2. Interlace/Non-Interlace Modes
• Interlace Mode and Skew Register (R8)-This write-only register is
used to control the interlace (2 modes) or non-interlace mode of the
display (Figure 3.2), and the display enable offset (skew or delay)
of the pixels. The mode is controlled by the 2 low-order bits, as shown
in Table 3.2. The Z-329 Card normally is operated in the non-interlace
mode. Bits 4 and 5 control the skew (delay) of the characters, and
bits 6 and 7 control the skew of the cursor. Tables 3.3 and 3.4 define
the function of these bits. The default value for this register is 02H
(2 decimal).