z86131 ZiLOG Semiconductor, z86131 Datasheet - Page 38

• Manufacturer Part Number: z86131
• Description: Ntsc Line 21 Decoder
• Manufacturer: ZiLOG Semiconductor

Z86129/130/131
NTSC Line 21 Decoder
INTERNAL REGISTERS (Continued)
Status Register Addresses = 0ChÐ0Dh
D
D, a1, a0, r2, r1, r0) of the first byte of 2 rating bytes re-
ceived.
D
High, it indicates that the incoming video program falls into
the set-up of program blocking.
D
(F)V, S, L, g2, g1, g0) of the second byte of 2 rating bytes
received.
D
ings. When it is High, it indicates that the recovered rating
of the incoming video program is valid.
Blocking Control Register= 0Eh
Figure 37. Blocking Control Register (Address = 0Ch)
D
grammed when a channel change occurs on a program-
blocking condition. These bits are optional control bits for
the program-blocking vertical frame period of time will be
incremented per the increment of 1 in this register.
D
feature in Z86130.
XDS Data Recovery
The Z86129/130/131 is able to recover Extended Data Ser-
vices (XDS) information from the input video signal. This
data, formatted according to EIA–608, can contain a wide
variety of information about current and future programs,
38
B
Bit
Bit
0
7
0
7
0
7
IT
ÐD
ÐB.
ÐD
ÐP.
ÐD
ÐBlock.
Figure 35. Status Register 1 (Address = 0Ch)
Figure 36. Status Register 2 (Address = 0Dh)
6
6
6
D
D
D
.
.
.
This bit indicates the validity of the recovered rat-
This bit indicates the blocking status. When it is
7
7
7
These bits have the same format as the 7 LSb’s(1,
This bits have the same format as the 7 LSb’s(1,
These bits extend the program blocking time as pro-
This bit enables/disables the program blocking
D
D
D
6
6
6
D
D
D
5
5
5
D
D
D
4
4
4
D
D
D
3
3
3
D
D
D
7
D
7
7
D
D
ÐD
ÐD
ÐD
2
2
2
0 ARE READ ONLY
0
0
are R/W.
are read only.
D
D
D
1
1
1
P R E L I M I N A R Y
D
D
D
0
0
0
.
the channel currently tuned, other channels and miscella-
neous data including time of day.
XDS data is only present in the even field. The Z86129 can
recover XDS data even while performing its normal caption
decoder or OSD functions.
XDS data packets are tagged according to a Class/Type sys-
tem defined by EIA–608. The Z86129/130/131(time infor-
mation only for the Z86131) 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 provid-
ed that permits selection of certain groups of packets that
are of use in specific 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 serial output registers of the
Z86129/130/131 immediately upon receipt and in the order
received. The DAV and RD2 bits of the Serial Status (SS)
register then go High, indicating the availability of two out-
put bytes. The external TV control processor is not required
to send a READ SELECT command in order to read these
data bytes.
When the XDS Filter register is set to 00h (the default state)
XDS recovery is disabled.
Caution: When XDS data recovery is enabled, the external
Some examples of Z86129/130/131 WRITE commands
that could be used to set the XDS Filter Register are indi-
cated in Table 23 (time information only for the Z86131).
The XDS Filter Register bit assignments are defined in the
Z86129/130/131 Internal Registers section, page 33 of this
document.
controller should never perform any other read oper-
ation, except SS reads, in the beginning of field 2.
The user can most easily accomplish this task by us-
ing the end of field (EOF) or data line end (DLE) in-
terrupt to locate the end of field 2 or the vertical
blanking interval (VBI) of field 1, and then perform
the READ SELECT and READ functions during this
portion of the video frame. Commands other than
READ SELECTS do not interfere with XDS data re-
covery regardless of their position in the video frame.
DS007200-TVX0199
ZiLOG