- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
210
12.2.6. VS Lock Mode (VSL)
In this mode, the camera’s vertical and horizontal phases are synchronized to an external video signal.
The reset operation is performed in the vertical direction, and the PLL operation is performed in the horizontal
direction. SGMODE is set to 2[h]. (See
System Configuration
The VS Lock Mode master signal is the external video signal (EXT-VIDEO). The 1Vpp external video
luminance signal (EXT-VIDEO-Y), which has passed through an external LPF and had its subcarrier
component removed, is input to the EXVIDEOY (pin 57) pin.
Inside the CXD3172AR, the input EXT-VIDEO-Y signal is divided between a vertical signal (EXT-VD) and a
horizontal signal (EXT-HD). EXT-VD resets the vertical counter inside the CXD3172AR. The EXT-HD signal is
phase-compared against the MCK-frequency-divided HD (MCK-HD) signal inside the CXD3172AR.
In addition, in VS Lock Mode (VSL), the 27.000MHz clock is used for input to ECK (pin 88). In this case, the
MODESEL (operation mode) setting is as shown in
. We recommend using X’tal oscillation for
the VCXO on the MCK side.
A system block diagram is shown in
. The external input signal is presented in
Fig 12.2-22 VS Lock (VSL) mode
Table 12.2-24 External I/O signals (VS Lock (VSL) Mode)
Pin Name(Pin No)
I/O
I/O signals
S0(44pin) IN
3.3V
connection
EXVIDEOY(57pin) IN
EXT-VIDEO-Y
(1Vpp:
analog
signal)
EXVIDEO(58pin)
OUT
DC bias supply to EXVIDEOY (pin 57)
* EXT-VIDEO should be passed through an LPF before being input to EXVIDEOY (pin 57). This serves to
remove the subcarrier component, and is a countermeasure against noise in cases where no external video
signal is input.
CXD3172AR
42
43
88
87
86
46
47
48
44
49
57
58
ESC
I
ES
CO
EC
K
PC
O
M
P
EXV
ID
EO
Y
EX
VID
E
O
S0
S1
S4
S3
S2
MCK
3.3V
LPF
(H-PLL)
VCXO
LPF
EXT-VIDEO
X'tal
(27.000MHz)