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Video Scaler v4.0 User Guide
UG805 March 1, 2011
Chapter 3:
Implementation
Some observations (not exclusively true for all conversions):
•
Generally, when up-scaling, or dealing with high definition (HD) rates, it is simplest
to use an input-side frame buffer. This does depend upon the available clock rates.
•
When down-scaling, it is often the case that the input-side frame buffer is not
required, because for every input line the scaler is required to generate a maximum of
one valid output line.
•
Generally, the output data does not conform to any standard. It is therefore not
possible to feed the output directly to a display driver. Usually, a frame buffer is
ultimately required to smooth the output data over an output frame period. The
output video stream is described later.
I/O Buffering, Clock Domains
Figure 3-2
shows the top level buffering, indicating the different clock domains, and the
scope of the control state-machines.
To support the many possibilities of input and output configurations, and to take
advantage of the fast FPGA fabric, the scaler core uses a separate clock domain from that
used in controlling data I/O. More information is given in
Chapter 9, Performance
about
how to calculate the minimum required operational clock frequency. It is also possible to
read the output of the scaler using a 3rd clock domain. These clock domains are isolated
from each other using asynchronous line buffers as shown in
Figure 3-2
. The control state-
machines monitor the I/O line buffers. They also monitor the current input and output line
numbers.
X-Ref Target - Figure 3-2
Figure 3-2:
Simplified Top Level Block Diagram, Indicating Clock-domains
$ATA&LOW
#ONTROL&LOW#LOCKS
VIDEO?IN?CLK
ACTIVE?VIDEO?IN
LINE?REQUEST
HBLANK?INVBLANK?IN
7RITESIDECONTROL
VIDEO?DATA?IN
O
O
E
D
I
V
K
L
C
?
N
I
O
E
D
I
V
UT?CLK
VIDEO?DATA?OUT
2EADSIDECONTROL
VIDEO?OUT?CLK
VIDEO?OUT?ALMOST?FULL
VIDEO?OUT?WE
#LK
#ONTROL
3TATE-ACHINES
!SYNC)NPUT
,INE"UFFER
!SYNC/UTPUT
,INE"UFFERS
3CALER-ODULE
5'???
3CALER#ORE
Содержание LogiCORE IP
Страница 1: ...LogiCORE IP Video Scaler v4 0 User Guide UG805 March 1 2011...
Страница 6: ...Video Scaler v4 0 User Guide www xilinx com UG805 March 1 2011...
Страница 14: ...14 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Preface About This Guide...
Страница 18: ...18 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Chapter 1 Introduction...
Страница 20: ...20 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Chapter 2 Overview...
Страница 70: ...70 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Chapter 9 Performance...
Страница 74: ...74 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Appendix A Use Cases...
Страница 92: ...92 www xilinx com Video Scaler v4 0 User Guide UG805 March 1 2011 Appendix B Programmer Guide...