M37274EFSP Datasheet, PDF (41/148 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER

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MITSUBISHI MICROCOMPUTERS
M37274EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
(1) Clamping Circuit and Low-pass Filter
This filter attenuates the noise of the composite video signal input
from the CVIN pin. The CVIN pin to which composite video signal is
input requires a capacitor (0.1 µF) coupling outside. Pull down the
CVIN pin with a resistor of hundreds of kiloohms to 1 M . In addition,
we recommend to install externally a simple low-pass filter using a
resistor and a capacitor at the CVIN pin (refer to Figure 25).
(2) Sync Slice Circuit
This circuit takes out a composite sync signal from the output signal
of the low-pass filter. Figure 25 shows the structure of the sync slice
register.
Sync Slice Register
b7 b6 b5 b4 b3 b2 b1 b0
0 0 0 0 1 0 1 _{Sync slice register (SSL) [Address 00E3 16]}
B
Name
0, 2 Fix these bits to “1.”
Functions
1, Fix these bits to “0.”
3 to 6
7 Vertical synchronous _{0: Method 1}
signal (Vsep) generating 1: Method 2
method selection bit
(SSL7)
After reset R W
0
RW
0
RW
0
RW
Fig. 35. Sync Slice Register
40