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7220 Datasheet, PDF (114/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER | |||
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FUNCTIONAL DESCRIPTION
2.11 CRT display function
2.11.8 Raster coloring function
R, G, B, and OUT1 output can be switched to MUTE output. MUTE output can color all displaying area
(raster) of screen.
For example, the case that pin B is specified for MUTE signal output is shown in Figure 2.11.18.
When the MUTE signal is output from pin B, the background of the entire screen is colored âBLUE.â Then,
a character data is output from pin R, for example. When B and R signal outputs are set to âcharacter is
outputâ by the color register at the character âIâ output, the output character is colored âYELLOWâ (âREDâ
mixed âBLUEâ) regardless of the OUT1 signal output.
When outputting the character âO,â the output character is colored only âREDâ that is not mixed âBLUEâ
by setting only R signal output to âcharacter is output.â However, in this case, set pin OUT1 to âblank is
output.â
The TV image can be also erase by setting the all R, G, and B pins to MUTE output. The MUTE signal
is output from pin OUT1 output, regardless of setting CRT display RAM for pin OUT1.
Whether ordinary video signal outputs or MUTE signal outputs from pins R, G, and B is controlled by bits
5 to 7 of the CRT port control register (refer to âFigure 2.11.17â).
A
HSYNC
R
B
OUT 1
Fig. 2.11.18 MUTE signal output example
âREDâ
âBLUEâ
A'
Signals across
A-A'
7220 Group Userâs Manual
2-87
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