
M37221M4H/M6H/M8H/MAH–XXXSP/FP M37221EASP/FP
Rev.1.00 Oct 01, 2002 page 54 of 110
REJ03B0134-0100Z
8.11 OSD FUNCTIONS
Table 8.11.1 outlines the OSD functions. This microcomputer incor-
porates an OSD control circuit of 24 characters ✕ 2 lines. OSD is
controlled by the CRT control 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 combina-
tion of up to 8 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 8.11.1).
The following shows the procedure how to display characters on the
CRT screen.
➀ Write the display character code in OSD RAM.
➁ Specify the display color by using the color register.
➂ Write the color register in which the display color is set in OSD
RAM.
④ Specify the vertical position by using the vertical position register.
➄ Specify the character size by using the character size register.
⑥ Specify the horizontal position by using the horizontal position
register.
⑦ Write the display enable bit to the designated block display flag of
the CRT control register. When this is done, the OSD starts ac-
cording to the input of the VSYNC signal.
Table 8.11.1 Features of Each Display Mode
Number of display characters 24 characters ✕ 2 lines
Dot structure 12 ✕ 16 dots
Kinds of characters 256 kinds
Kinds of character sizes 3 kinds
Attribute Border (black)
Character font coloring 1 screen : 8 kinds (per character unit)
Character background coloring 1 screen : 8 kinds (per character unit)
OSD output R, G, B
Display position Horizontal: 64 levels, Vertical: 128 levels
Display expansion (multiline display) Possible
Parameter Functions
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