Analog Devices Advantiv ADV7604 Hardware Manual page 268

value of FCL multiplied by 256 gives one field length count in 28.6363 MHz (XTAL)
clocks.
Note : CHx = CH1 or CH2 in the above register descriptions representing channel 1 and channel 2
related registers.
By interpreting these four parameters, it is possible to distinguish between the different types of
input signals.
In ADV7604, there are three operational modes for the STDI block:
• Continuous mode :
The STDI block performs continuous measurements on lock/unlock bases and updates the
corresponding I
• Real-time continuous mode :
The STDI block performs continuous measurement regardless of the lock/unlock bases and
always updates real-time measurement data to the corresponding I
• Single shot mode:
The STDI block waits for a trigger (0 to 1 transition on CHx_TRIG_STDI) to start the
measurements. Single-shot mode can be useful in complex systems where the scheduling of
functions is important.
A data valid flag, CHx_STDI_DVALID, is provided, which is based on the status of the
horizontal/vertical lock of the block and is held low during the measurements. The four parameters
should only be read after the
mode. In real-time continuous mode, the ADV7604 allows the user to monitor the real-time timing
measurement regardless of the
on the readback values.
Notes:
• Synchronization type pulses include horizontal synchronization, equalization and serration
pulses, and Macrovision pulses.
• Macrovision pseudo synchronization and AGC pulses are counted by the STDI block in
normal readback mode. This does not prohibit the identification of the video signal.
• The
CHx_TRIG_STDI
setting the CHx_TRIG_STDI
by writing a 0 to it. This second write (to clear the flag) can be done at any time and does
not have any effect on running measurements. It also does not invalidate previous
measurement results.
• The ADV7604 only measures those parameters, but does not take any action based upon
them. The part does not reconfigure itself. To avoid unforeseen problems in the scheduling
of a system controller, the part merely helps to identify the input.
• Since real-time continuous mode provides the capability to monitor the real-time
measurement data regardless of the block lock status, the user should be aware that the
timing readback values may not be a valid readback measurement in this mode.
Rev. F August 2010
2
C registers based on the lock status bit (STDI_DVALID).
P
P
CHx_STDI_DVALID
CHx_STDI_DVALID
flag is not self clearing. The measurements are only started upon
flag. This means that after setting it, it must be cleared again
flag has gone high for the continuous/single shot
flag. Refer to Section
268
ADV7604
2
C registers.
10.8.3.4 for information