Table of Contents
Advertisement
FUNCTIONAL DESCRIPTION
2.11 CRT display function
2.11.3 Memory for display
There are 2 types of display memory: CRT display ROM (addresses 10000
(masked) character dot data and CRT display RAM (addresses 0600
and characters to be displayed. Each type of display memory is described below.
(1) CRT display ROM (addresses 10000
CRT display ROM stores dot pattern data for characters to be displayed. When actually displaying
characters stored in this ROM, it is necessary to specify them by writing the character code inherent
to each character (code determined based on the addresses in CRT display ROM) into CRT display
RAM.
CRT display ROM has a capacity of 8 K bytes. Since 32 bytes are required for 1 character data, the
ROM can stores up to 256 kinds of characters.
CRT display ROM is broadly divided into 2 areas. The [vertical 16 dots]
dots] data of display characters are stored in addresses 10000
the [vertical 16 dots]
addresses 10800
high-order 4 bits of the data to be written to addresses 10800
must be set to "1" (by writing data FX
10XX0
16
or
11XX0
16
10XXF
16
or
11XXF
16
Fig. 2.11.10 Example of display character data storing form
2-78
[horizontal (right side) 4 dots] data of display characters are stored in
to 10FFF
, 11800
16
16
16
b7
b0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
1
0
0
0
0
1
0
1
0
0
0
0
1
0
0
0
1
0
0
0
1
0
0
0
1
0
0
0
1
0
0
0
1
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
1
1
1
1
1
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7220 Group User's Manual
to 11FFF
)
16
16
to 11FFF
(refer to "Figure 2.11.10"). Note however that the
16
).
16
b7
1
1
1
10XX0
16
+800
16
1
1
1
or
1
1
1
11XX0
16
1
1
1
+800
16
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
10XXF
16
+800
16
or
11XXF
16
+800
16
to 11FFF
16
16
to 06B7
) used to specify the colors
16
16
[horizontal (left side) 8
to 107FF
and 11000
16
16
to 10FFF
and 11800
16
16
b3
b0
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
1
0
1
0
0
0
0
1
0
0
0
0
1
1
0
0
0
1
1
0
0
0
1
1
0
0
0
1
0
1
0
0
1
0
1
0
0
0
1
0
0
1
0
0
0
0
1
1
0
0
0
0
) used to store
to 117FF
;
16
16
to 11FFF
16
16
Advertisement
Table of Contents
