z86230 ZiLOG Semiconductor, z86230 Datasheet - Page 35

• Manufacturer Part Number: z86230
• Description: Advanced Violence Blocking And Ntsc Line 21 Xds
• Manufacturer: ZiLOG Semiconductor

6.2 XDS D
PS000400-TVC0499
ATA
R
ECOVERY
XDS D
D
The Z86230 is able to recover Extended Data Services (XDS) information from
the input video signal. This data, formatted according to EIA-608A, can contain a
wide variety of information about current and future programs, the channel cur-
rently tuned, other channels, and miscellaneous data, including time of day.
XDS data packets are tagged according to a Class/Type system defined by EIA-
608A. The Z86230 can be programmed to filter the XDS data stream to extract
only the classes of interest to the application. An additional level of filtering is
provided that permits selection of certain groups of packets that are of use in spe-
cific applications. XDS filtering reduces the traffic on the serial bus, reduces the
load of the TV/VCR control processor, and simplifies external XDS decoding.
XDS data recovery is enabled by selecting one or more classes in the XDS Filter
Register. Optionally, a secondary filter code can be specified which further limits
the packets to be recovered. When XDS recovery is enabled, filtered data pairs are
loaded into the first two data locations of Bank 0 immediately upon receipt. The
DAV
ability of two output bytes.
When the XDS Filter Register is set to
disabled.
C
form any other read operation, except
other than READ SELECTs do not interfere with XDS data recovery regardless of their
position in the video frame.
Some examples of Z86230
Filter Register are indicated in Table 28. The XDS Filter Register bit assignments
are defined in Table 30.
AUTION
1
-D
7
bit of the Serial Status Register (
-Res.
ATA
:
When XDS data recovery is enabled, the external controller should never per-
R
ECOVERY
Reserved. These bits must be kept Low(0).
Z86230—PRELIMINARY
WRITE
SSR
commands that could be used to set the XDS
SSR
reads, in the beginning of Field 2. Commands
00h
) then goes High, indicating the avail-
(the default state), XDS recovery is
C
ONTROL
R
EGISTERS
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