Z90251 Datasheet, PDF (12/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
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The OSD module supports 10 rows by 24 columns of characters. Each character
color can be specified. There are eight foreground colors and eight background
colors. When the foreground and background colors are the same, the
background is transparent.
If Row, Second color and Character set are defined, an analog bar line can be
displayed for volume control, signal levels, and tuning.
The OSD can display four character sizes:
• 1X (14 x 18 pixels)
• 2X (28 x 36 pixels)
• Double width (28 x 18 pixels)
• Double height (14 x36 pixels)
Inter-row spacing can be programmed within 0 to 15 Horizontal scan lines. Using
multiple characters with zero inter-row spacing allows the creation of large psuedo
icons.
A 14-bit Pulse Width Modulator (PWM) port provides necessary voltage resolution
for a voltage synthesizer tuning system. Ten 6-bit PWM ports are used to control
audio (base, treble, balance and volume) and video (contrast, brightness, color,
tint and sharpness) signal levels.
There are 27 I/O pins grouped into four ports. These I/O pins can be configured
through software to provide timing, status signals, serial and parallel input and
output.
For real-time events, such as counting, timing and data communication, two on-
chip counter/timers are implemented. The Z90255 is packaged in a 42-pin SDIP
and provides an ideal, reliable solution for high-volume consumer television
applications.
PS001301-0800