msm7654 Oki Semiconductor, msm7654 Datasheet - Page 43

• Manufacturer Part Number: msm7654
• Description: Ntsc/pal Digital Video Encoder
• Manufacturer: Oki Semiconductor

Slave Mode
When in the slave mode, the encoder can receive the subcarrier-phase reset signal from the
external GENLOCK pin. The subcarrier-phase pulse should be input at the timing that meets the
AC characteristics. If the GENLOCK pulse is input to the encoder in the NTSC mode, the
subcarrier phase is reset when the pulse reaches the 4th field. And if the GENLOCK pulse is input
to the encoder in the PAL mode, the subcarrier phase is reset when the pulse reaches the eighth
field.
5 CLKX2 pulses (Genlock setup time: Tgen) are required for the time from when the reset signal
is input to the GENLOCK pin to when the internal GENLOCK flag is set. Thus, if the GENLOCK
pulse is input 5 CLKX2 pulses before the HSYNC_L and VSYNC_L signals at the first field are
input, the subcarrier phase is reset at the first field after the first input even if the internal state
of the encoder is any field. The subcarrier phase, however, cannot be reset if the GENLOCK pin
is fixed high.
(1) Input Timing (Slave mode)
¡ Semiconductor
CLKX2
GENLOCK (input)
CLKX1
(Internal signal)
Genlock flag
(Internal signal)
HSYNC_L (Input)
VSYNC_L (Input)
GENLOCK Input Timing
T
gen
MSM7654
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