M37270MF Datasheet, PDF (26/94 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER

MITSUBISHI MICROCOMPUTERS
M37270MF-XXXSP
M37270EF-XXXSP, M37270EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
DATA SLICER
The M37270MF-XXXSP includes the data slicer function for the
closed caption decoder (referred to as the CCD). This function takes
out the caption data superimposed in the vertical blanking interval of
a composite video signal. A composite video signal which makes
the sync chip’s polarity negative is input to the CVIN pin.
When the data slicer function is not used, the data slicer circuit can
be cut off by setting bit 0 of the data slicer control register 1 (address
00EA16) to “0.” Also, the timing signal generating circuit can be cut
off by setting bit 0 of data slicer control register 2 (address 00EB16)
to “0.” These settings can realize the low-power dissipation.
Composite
video
signal
0.1 F ₄₇₀
Hundred of kiloohms
to 1 M
560 pF _{1 F}
CVIN
HSYNC
1k
15 k
200 pF
HLF RVC O
Sync pulse counter
register
(address 020F16)
Synchr onizing
signal counter
Clock run-in register 2
(address 00E 716)
1 00 11 1
Clamping
circuit
Data slicer control register 2
(address 00EB16)
Low-pass
filter
Sync slice
circuit
Synchronizing
separation
circuit
0 00
Data slicer control register 1
(address 00E A16)
Timing signal
0 00
generating
circuit
Data slicer ON/OFF
Window register
VHOLD
1000 pF
Reference
voltage
generating
circuit
+
–
Comparator
Clock run-in
determination
circuit
Data slice line
specification
(address 00E216)
00
0 10 1
Clock run-in register 1
(address 00E616)
circuit
Data slicer control
1 00
register 3
(address 021016)
Start bit detecting
Caption position register
(address 00E016)
Clock run-in detect
circuit
register 3
(address 020816)
Start bit position register
Clock run-in
register 3
Data clock
generating circuit
(address 00E116)
(address 0209 16)
Clock run-in detect register 1
External circuit
16-bit shift register
(address 00E816)
Note : Make the length of wiring which
is connected to VHOLD, HLF,
RVCO and CVIN pin as short as
possible so that a leakage
current may not be generated
when mounting a resistor or a
capacitor on each pin.
Sync slice register 3
Data register 2
(address 00E516)
high-order
Data register 4
(address 00ED16)
low - order
Clock run-in detect register 2
(address 00E916)
Data register 1
(address 00E416) _{Interrupt request}
generating circuit
Data slicer
interrupt
request
(address 00E316)
Data register 3
0 00 01 01
(address 00EC16)
Data bus
Fig. 19. Data slicer block diagram
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