M37280MF Datasheet, PDF (59/178 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
M37280MF–XXXSP, M37280MK–XXXSP
M37280EKSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
12.10.5 Timing Signal Generating Circuit
This circuit generates a reference clock which is 832 times as large
as the horizontal synchronous signal frequency. It also generates
various timing signals on the basis of the reference clock, horizontal
synchronous signal and vertical synchronizing signal. The circuit
operates by setting bit 0 of data slicer control register 1 (address
00E016) to “1.”
The reference clock can be used as a display clock for OSD function
in addition to the data slicer. The HSYNC signal can be used as a
count source instead of the composite sync signal. However, when
the HSYNC signal is selected, the data slicer cannot be used. A count
source of the reference clock can be selected by bit 2 of data slicer
control register 1 (address 00E016).
For the pins HLF, connect a resistor and a capacitor as shown in
Figure 12.10.1. Make the length of wiring which is connected to these
pins as short as possible so that a leakage current may not be gener-
ated.
Note: It takes a few tens of milliseconds until the reference clock becomes
stable after the data slicer and the timing signal generating circuit are
started. In this period, various timing signals, Hsep signals and Vsep sig-
nals become unstable. For this reason, take stabilization time into con-
sideration when programming.
Composite
sync signal
Bit 5 of DSC2
0
1
1
AB
Fig. 12.10.7 Determination of V-pulse Waveform
Rev. 1.0
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