Control Data Corporation INFORMATION SYSTEMS TERMINAL II Hardware Maintenance Manual page 93

Increasing the address by one is equivalent to
moving one dot to the bottom on the screen (still
controlling eight horizontal dots).
There are 512 horizontal lines within a column.
The lower 9 bits of the 16-bit refresh memory
address determine 1 of the possible 512 lines.
The next 6 bits (A09-A14) of the refresh memory
address select 1 of the 64 vertical columns (each
column is 8 bits, or dots, wide). Increasing the
column address by one is equivalent to selecting
the next column to the right.
Each address uniquely selects a group or set of 8 bits
(dots). Selection of a bit or bits within this group is
accomplished by data manipulation.
For example, write a 1 and then a 0 in the screen position
located 21 dots to the right and 9 dots below the upper
left corner dot (figure 4-18). Do not modify any other
data on the screen.
o
I
2
3
4
LINE
l:
7
8
9
10
COLUMN 0 COLUMN I COLUMN 2
A
.&. A
" I I I I I I " I I I I 2 2 2 2'''"2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
'III",
Figure 4-18. Address 840916
82100083 B
I
I
1
03357
4-31