Z8623012SSG Datasheet, PDF(35/61 Page) Zilog, Inc. – ADVANCED PROGRAM BLOCKING AND NTSC LINE 21 XDS DECODER

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

Z8623012SSG Datasheet, PDF (35/61 Pages) Zilog, Inc. – ADVANCED PROGRAM BLOCKING AND NTSC LINE 21 XDS DECODER

◁

XDS DATA RECOVERY

CONTROL REGISTERS

D1-D7-Res. Reserved. These bits must be kept Low(0).

6.2 XDS DATA RECOVERY

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 deï¬ned by EIA-

608A. The Z86230 can be programmed to ï¬lter the XDS data stream to extract

only the classes of interest to the application. An additional level of ï¬ltering is

provided that permits selection of certain groups of packets that are of use in spe-

ciï¬c applications. XDS ï¬ltering reduces the trafï¬c on the serial bus, reduces the

load of the TV/VCR control processor, and simpliï¬es external XDS decoding.

XDS data recovery is enabled by selecting one or more classes in the XDS Filter

the packets to be recovered. When XDS recovery is enabled, ï¬ltered data pairs are

loaded into the ï¬rst two data locations of Bank 0 immediately upon receipt. The

DAV bit of the Serial Status Register (SSR) then goes High, indicating the avail-

ability of two output 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 controller should never per-

form any other read operation, except SSR reads, in the beginning of Field 2. Commands

other than READ SELECTs do not interfere with XDS data recovery regardless of their

position in the video frame.

Some examples of Z86230 WRITE commands that could be used to set the XDS

Filter Register are indicated in Table 28. The XDS Filter Register bit assignments

are deï¬ned in Table 30.

PS000401-TVC0699

Z86230âPRELIMINARY

▷