z86230 ZiLOG Semiconductor, z86230 Datasheet - Page 36

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

6.2.1 Filtered XDS Data Format
36
C
ONTROL
T
Filtered XDS data is output from the Z86230 in the order it is received on Line 21.
In other words, think of the Z86230 XDS filter function as creating a new, smaller
stream of XDS data packets. This new data stream looks exactly as though the
Class and Type specified in the XDS Filter Register (
encoded on Line 21 of Field 2. The filtered data output from the Z86230 is in full
compliance with EIA-608 specifications for XDS data streams (headers and con-
trol codes intact). Refer to the
exception to this rule.
XDS data and header information (including
mands) are passed through the filter for the XDS Class and Type specified in the
XDS Filter Register. All other Line 21 data is filtered out. This data does not out-
put or generate a data available flag (
To properly read filtered XDS data from the Z86230, the master device must first
write the XDS Filter Register (
mation. For example, in the Z86230, in order to extract ONLY the Line 21 Pro-
gram Rating information, the master must write the value
Register. The master should then poll the state of the
DAV = 1
As soon as
mode (XDS data bytes always arrive in pairs, so it is safe to read the first 2 bytes
of read bank 0 when
bytes, which in this case are the first 2 bytes of the Current Class, Program Rating
Type XDS data stream encountered on Line21, Field 2. The master device must
then interpret those 2 bytes according to EIA-608 specifications for Current Class,
Program Rating Type data. Refer to EIA-608 for the appropriate data formats.
{WRITE Command,
Filter Code}
{C5,41}
{C5,61}
{C5,1F}
{C5,01}
{C5,28}
{C5,9F}
ABLE
R
EGISTERS
28. XDS D
.
DAV = 1
Z86230—PRELIMINARY
ATA
, the master may initiate a 3-byte
DAV = 1
XDS Filter Output
All In Band; Current Class packets recovered.
Program Rating; Current Class packets recovered. This
filter may be used for Program Blocking Data Packet
Recovery.
All XDS packets recovered.
All Current Class packets recovered.
Time information recovered. This filter extracts the
Time of Day (TOD) and Local Time Zone (LTZ) packets
from the Miscellaneous Class data.
This filter may be used to implement Auto Clock-
Setting in TVs, and VCRs.
VCR Information recovered. This filter selects TOD, LTZ,
Net ID, Local Call Letters, Impulse Capture, Tape Delay,
Composite 2, and Out-of-Band Channel Number
packets for recovery.
E
XTRACTION
in the SSB). A 3-byte
N
05h
OTE
E
) with its required XDS Class and Type infor-
paragraph on the next page for a special
XAMPLE
DAV
) in the Serial Status Register (
F
START
ILTER
S
READ
,
ETTINGS
05h
DAV
READ
CONTINUE
) are the only data
61h
bit in the
always yields two data
in
PS000400-TVC0499
XDS D
RBS
to the XDS Filter
, and
SSR
Read Bank 0
ATA
END
SSR
R
until
ECOVERY
com-
).