M37221M6_03 Datasheet, PDF (33/62 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER

MITSUBISHI MICROCOMPUTERS
M37221M6-XXXSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
with ON-SCREEN DISPLAY CONTROLLER
CRT DISPLAY FUNCTIONS
(1) Outline of CRT Display Functions
Table 8 outlines the CRT display functions of the M37221M6-XXXSP.
The M37221M6-XXXSP incorporates a CRT display control circuit of
24 characters ! 2 lines. CRT display is controlled by the CRT con-
trol register. Up to 256 kinds of characters can be displayed. The
colors can be specified for each character and up to 4 kinds of colors
can be displayed on one screen. A combination of up to 7 colors can
be obtained by using each output signal (R, G, and B).
Characters are displayed in a 12 ! 16 dots configuration to obtain
smooth character patterns (refer to Figure 31).
The following shows the procedure how to display characters on the
CRT screen.
ΠWrite the display character code in the display RAM.
 Specify the display color by using the color register.
Ž Write the color register in which the display color is set in the dis-
play RAM.
 Specify the vertical position by using the vertical position register.
 Specify the character size by using the character size register.
‘ Specify the horizontal position by using the horizontal position
register.
’ Write the display enable bit to the designated block display flag of
the CRT control register. When this is done, the CRT display starts
according to the input of the VSYNC signal.
The CRT display circuit has an extended display mode. This mode
allows multiple lines (3 lines or more) to be displayed on the screen
by interrupting the display each time one line is displayed and rewrit-
ing data in the block for which display is terminated by software.
Figure 32 shows the structure of the CRT display control register.
Figure 33 shows the block diagram of the CRT display control circuit.
Table 8. Outline of CRT display functions
Parameter
Number of display
characters
Dot structure
Kinds of characters
Kinds of character sizes
Color
Kinds of colors
Coloring unit
Display expansion
Raster coloring
Character background
coloring
Functions
24 characters ! 2 lines
12 ! 16 dots (refer to Figure 31)
256 kinds
3 kinds
1 screen : 4 kinds, maximum 7 kinds
A character
Possible (multiline display)
Possible (maximum 7 kinds)
Possible (a character unit, 1 screen
: 4 kinds, maximum 7 kinds)
12 dots
16 dots
Fig. 31. CRT display character configuration
7
0
CRT control register
(CC: address 00EA16)
All-blocks display control bit (Note)
0 : All-blocks display off
1 : All-blocks display on
Block 1 display control bit
0 : Block 1 display off
1 : Block 1 display on
Block 2 display control bit
0 : Block 2 display off
1 : Block 2 display on
P10/OUT2 pin switch bit
0 : P10
1 : OUT2
Note: Display is controlled by logical product (AND) between the
all-blocks display control bit and each block control bit.
Fig. 32. Structure of CRT control register
32