EVAL-ADV7314EB Analog Devices Inc, EVAL-ADV7314EB Datasheet - Page 37

• Manufacturer Part Number: EVAL-ADV7314EB
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADV7314EB

• Lead Free Status / Rohs Status: Not Compliant

SD Real-Time Control, Subcarrier Reset, and Timing Reset
[Subaddress 44h, Bit 2,1]
Together with the RTC_SCR_TR pin and SD Mode Register 3,
the ADV7314 can be used in timing reset mode, subcarrier phase
reset mode, or RTC mode.
Timing Reset Mode
A timing reset is achieved in a low-to-high transition on the
RTC_SCR_TR pin (Pin 31). In this state, the horizontal and
vertical counters will remain reset. On releasing this pin (set to
low), the internal counters will commence counting again, the
field count will start on Field 1, and the subcarrier phase will
be reset.
The minimum time the pin has to be held high is one clock
cycle; otherwise this reset signal might not be recognized.
This timing reset applies to the SD timing counters only.
Subcarrier Phase Reset
A low-to-high transition on the RTC_SCR_TR pin (Pin 31) will
reset the subcarrier phase to zero on the field following the
subcarrier phase reset when the SD RTC/TR/SCR control bits
at Address 44h are set to 01.
REV. 0
DISPLAY
307
NO TIMING RESET APPLIED
TIMING RESET APPLIED
NO F
F
SC
307
307
307
RESET APPLIED
SC
RESET APPLIED
DISPLAY
DISPLAY
DISPLAY
310
310
310
1
Figure 30. Subcarrier Reset Timing Diagram
START OF FIELD 1
Figure 29. Timing Reset Timing Diagram
2
3
313
313
313
4
START OF FIELD 4 OR 8
START OF FIELD 4 OR 8
START OF FIELD 4 OR 8
5
–37–
6
This reset signal will have to be held high for a minimum of one
clock cycle.
Since the field counter is not reset, it is recommended that the
reset signal should be applied in Field 7 [PAL] or Field 3
[NTSC]. The reset of the phase will then occur on the next
field, i.e., Field 1, being lined up correctly with the internal
counters. The field count register at Address 7Bh can be used to
identify the number of the active field.
RTC Mode
In RTC mode, the ADV7314 can be used to lock to an external
video source. The real-time control mode allows the ADV7314
to automatically alter the subcarrier frequency to compensate
for line length variations. When the part is connected to a device
that outputs a digital datastream in the RTC format (such as an
ADV7183A video decoder, see Figure 31), the part will auto-
matically change to the compensated subcarrier frequency on a
line by line basis. This digital datastream is 67 bits wide and the
subcarrier is contained in Bits 0 to 21. Each bit is two clock
cycles long. 00h should be written into all four subcarrier
frequency registers when using this mode.
F
7
SC
PHASE = FIELD 1
21
F
320
F
SC
320
320
SC
F
PHASE = FIELD 4 OR 8
SC
PHASE = FIELD 4 OR 8
PHASE = FIELD 1
TIMING RESET PULSE
F
SC
RESET PULSE
ADV7314