Cirrus Logic Crystal SDB4954A, Руководство пользователя

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CDB4954A/55A
4
1. CDB4954A/55A SYSTEM OVERVIEW
The CDB4954A/55A Evaluation Board allows the
CS4954/55 NTSC/PAL Digital Video Encoder ICs
from Cirrus Logic to be evaluated with a variety of
internal and external video signals. DIP switches on
the evaluation board allow external serial or parallel
video to drive the CS4954/55, display test patterns
contained in the evaluation board’s control FPGA,
and display NTSC images stored in FLASH. When
the CDB4954A/55A (Microsoft Windows95
®
,
Windows 98
®
, Windows NT
®
, and Windows
2000
®
compatible) software is used, bitmaps up to
720x480 pixels may be converted to CCIR656 PAL
or NTSC files, downloaded to SDRAM on the eval-
uation board and played from SDRAM through the
CS4954/55. In addition, NTSC CCIR656 files can
be stored to FLASH memory on the evaluation
board for later play back. The CDB4954A/55A
board supports Composite, RGB and S-Video out-
puts simultaneously.
The CDB4954A/55A has been partitioned into 6
schematics shown in
Figure 5 , Figure 6 , Figure 7 ,
Figure 8 , Figure 9 , and Figure 10 . Notice that the
partitioned schematics show the interconnections
between the pages.
2. SETUP ACTIVITIES
Setup of the CDB4954A/55A is straightforward.
DC Power is supplied to the board either via the
supplied “wall wart” style power supply or by us-
ing the binding posts on the board (but not both!)
When the board is powered, the Power In LED
(D6) will illuminate. If you're planning to use the
supplied software, you will need to copy the files
on the distribution disk shipped with the evaluation
board to your hard disk drive. You should use the
supplied 9-pin serial cable to connect your IBM
®
PC (or compatible) to the 9-pin D-Sub connector
(labeled J6, RS-232) on the CDB4954A/55A.
2.1 DIP Switch Options
If you use the CDB4954A/55A Evaluation Board
without a PC (i.e. in the standalone mode), use the
followings to set up the board using the 8 position
dip switch. The dip switch positions are marked 1-
8. The individual switches select these functions:
Switches 1-4 select different operating modes. (Re-
fer to
Table 3 on page 8 for more information.)
Switch 5 - Not Used
Switch 6 - PAL/NTSC data format.
Switch 7 - Pedestal Offset ON/OFF.
Switch 8 - Clipping Input Signals ON/OFF.
2.2 Control Port Software
The CDB4954A/55A is shipped with Microsoft
®
Windows
®
based software for interfacing with the
CS4954/55 via the DB9 connector, J26. This soft-
ware allows the user to have complete access to the
control registers of the CS4954/55, as well as the
ability to access some features of the on-board FP-
GA. A comprehensive online Help is included.
2.2.1 Changing a CS4954/5 or FPGA Reg-
ister
There are two ways to change the values of either
CS4954/55 or FPGA registers. When a register
check box is checked, the corresponding register
bit is set to a “1”. When unchecked, the bit is set to
“0”. The first approach, shown on
Figure 1 on page
5 , is to check or uncheck particular bit values in the
desired register. For example, in Figure 1 , the
CONTROL_0 configuration register of the
CS4954/55 is set for CCIR656 mode (CCIR656
check box checked) and for video input from
V[7:0] (IN_MODE check box checked). In addi-
tion, the background color generated by the
CS4954/55 is set to blue (BLUE1 and BLUE0
check boxes are checked). The second approach is
to click the register label above any set of register
check boxes. This brings up a dialog which is