MTV230MV64 View Datasheet(PDF) - Myson Century Inc
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MTV230MV64 Datasheet PDF : 31 Pages
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MYSON
TECHNOLOGY
MTV230M
(Rev 1.0)
6. H/V SYNC Processing
The H/V SYNC processing block performs the functions of composite signal separation/insertion, SYNC
inputs presence check, frequency counting, polarity detection and H/V output polarity control. The present
and frequency function block treat any pulse shorter than one OSC period as noise.
VSYNC
Digital Filter
Present
Check
Vpre
Polarity Check &
Freq. Count
Vfreq
Vpol
Vbpl
CVSYNC
XOR
XOR VBLANK
HSYNC
Present
Check
CVpre
Digital Filter
Polarity Check &
Sync Seperator
Hpol
Present Check &
Freq. Count
Composite
Pulse Insert
Hpre
Hfreq
Hbpl
XOR
XOR
HBLANK
H/V SYNC Processor Block Diagram
6.1 Composite SYNC Separation/Insertion
The MTV230M continuously monitors the input HSYNC, if the vertical SYNC pulse can be extracted from the
input, a CVpre flag is set and users can select the extracted "CVSYNC" for the source of polarity check,
frequency count, and VBLANK output. The CVSYNC will have 8us delay compared to the original signal.
The MTV230M can also insert pulse to HBLANK output during composite active time of VSYNC. The width
of the insert pulse is 1/8 HSYNC period and the insertion frequency can adapt to original HSYNC. The insert
pulse of HBLANK can be disabled or enabled by setting “NoHins” control bit.
6.2 H/V Frequency Counter
MTV230M can discriminate HSYNC/VSYNC frequency and saves the information in XFRs. The 14 bits
Hcounter counts the time of 64xHSYNC period, then loads the result into the HCNTH/HCNTL latch. The
output value will be [(128000000/H-Freq) - 1], updated once per VSYNC/CVSYNC period when
VSYNC/CVSYNC is present or continuously updated when VSYNC/CVSYNC is non-present. The 12 bits
Vcounter counts the time between two VSYNC pulses, then loads the result into the VCNTH/VCNTL latch.
The output value will be (62500/V-Freq), updated every VSYNC/CVSYNC period. An extra overflow bit
indicates the condition of H/V counter overflow. The VFchg/HFchg interrupt is set when VCNT/HCNT value
changes or overflowes. Table 6.2.1 and table 6.2.2 show the HCNT/VCNT value under the operations of
12MHz.
Revision 1.0
- 9-
2000/11/15
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