7220 Datasheet, PDF (104/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

FUNCTIONAL DESCRIPTION
2.11 CRT display function
2.11.2 Character size
The size of characters to be displayed can select from 3 sizes for each block. Set a character size by the
character size register (address 00E416).
The character size in block 1 can be specified by bits 0 and 1 of the character size register; the character
size in block 2 can be specified by bits 2 and 3. Figure 2.11.8 shows the character size register.
Character Size Register
b7 b6 b5 b4 b3 b2 b1 b0
Character size register (CS) [Address 00E4 16]
B
Name
Functions
0, 1 Character size of block 1
selection bits
(CS10, CS11)
00 : Minimum size
01 : Medium size
10 : Large size
11 : Do not set.
2,3 Character size of block 2
selection bits
(CS20,CS21)
00 : Minimum size
01 : Medium size
10 : Large size
11 : Do not set.
4
to
7
Nothing is assigned. These bits are write disable bits.
When these bits are read out, the values are “0.”
After reset R W
Indeterminate R W
Indeterminate R W
0
R—
Fig. 2.11.8 Character size register (address 00E416)
The character size can select three sizes: minimum
size, medium size, and large size. Each character
size is determined with the number of scanning lines
in the height (vertical) direction and the oscillation
cycle for display (= TC) in the width (horizontal)
direction.
The minimum size consists of [1 scanning line] ! [1
TC]; the medium size consists of [2 scanning lines]
! [2 TC]; and the large size consists of [3 scanning
lines] ! [3 TC]. Table 2.11.2 shows the relationship
between the set values in the character size register
and the character sizes.
Display start
position
Minimum size
Medium size
Large size
Fig. 2.11.9 Display start position (horizontal
direction) for each character size
Table 2.11.2 Relationship between set value in character size register and character sizes
Set values in character size register
Width (horizontal) direction Height (vertical) direction
CSn1
CSn0
Character size
TC: oscillation cycle for display
scanning lines
0
0
Minimum
1 TC
1 line
0
1
Medium
2 TC
2 lines
1
0
Large
3 TC
1
1
This is not available.
3 lines
Note: The display start position in the horizontal direction is not affected by the character size. In other
words, the horizontal display start position is common to all blocks even when the character size
varies with each block (refer to “Figure 2.11.9”).
7220 Group User’s Manual
2-77