Z90251 Datasheet, PDF (47/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
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5.7 Character Size and Smoothing Effect
The Z90255 supports four character sizes: 1X, 2X, double width, and double
height. The 2X size duplicates each pixel horizontally and vertically to reach
double size. Figure 14 shows a character at 1X, 2X without smoothing, and 2X
with smoothing.
Smoothing means enhancing a character to improve its appearance. This effect
can be applied to 2X and double width characters, and is enabled and disabled in
DISP_ATTR: 03h: Bank A (4).
Check the effect of smoothing on 2X and double width characters before finalizing
OSD programming.
1X
2X
Figure 14 Smoothing Effect on 2X Character Size
After Smoothing
PS001301-0800