Renesas PROM Programming Adapter PCA7408 Manual do Utilizador descarregar pdf (Página 54)

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

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

1 2 ... 49 50 51 52 53 54 55 56 57 58 59 ... 111 112

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