saa569x NXP Semiconductors, saa569x Datasheet - Page 65

• Manufacturer Part Number: saa569x
• Description: Enhanced Tv Microcontrollers With On-screen Display Osd
• Manufacturer: NXP Semiconductors

Philips Semiconductors
22.1.6.9
When a packet 27, designation code 0 is detected,
whether or not it is acquired, bit TXT13.FASTEXT is set.
If the device is receiving 525-line Teletext, a packet
X/0/27/0 is required to set the flag. The flag can be reset
by writing a logic 0 into the SFR-bit.
When a packet 8/30 is detected (or a packet 4/30 when
the device is receiving a 525-line transmission), flag
TXT13.PKT 8/30 is set. The flag can be reset by writing a
logic 0 into the SFR-bit.
22.1.6.10 Broadcast Service Data Detection
When a packet 8/30 is detected (or a packet 4/30 when
the device is receiving a 525-line transmission), flag
TXT13. PKT 8/30 is set. The flag can be reset by writing a
logic 0 into the SFR-bit.
22.1.6.11 VPS acquisition
When bit TXT0.VPS ON is set, any VPS data present on
line 16, field 0 of the CVBS signal at the input of the
Teletext decoder is error checked and stored in row 25,
block 9 of the basic page memory, see Fig.24. The device
automatically detects whether Teletext or VPS is being
transmitted on this line and decodes the data
appropriately.
Each VPS byte in the memory consists of four biphase
decoded data bits (bits 0 to 3), a biphase error flag (bit 4)
and three logic 0s (bits 5 to 7).
The most significant bit of the VPS data cannot be set to
logic 1.
Bit TXT13.VPS Received is set by the hardware whenever
VPS data is acquired.
Full details of the VPS system can be found in the
specification “Domestic Video Program Delivery Control
System (PDC); EBU Tech. 3262-E”.
2002 May 06
handbook, full pagewidth
Enhanced TV microcontrollers with
On-Screen Display (OSD)
Fastext detection
row 25
column
0
teletext page
header data
9
10
byte 11
VPS
Fig.24 VPS data storage.
11
12
byte 12
VPS
13 14
65
byte 13
22.1.7
The SAA567x; SAA569x family is capable of acquiring
Level 1.5 625-line and 525-line World System Teletext.
22.1.8
The WSS data transmitted on line 23 gives information on
the aspect ratio and display position of the transmitted
picture, the position of subtitles and on the camera/film
mode. Some additional bits are reserved for future use.
A total of 14 data bits are transmitted.
All of the available data bits transmitted by the WSS signal
are captured and stored in SFRs WSS1, WSS2 and
WSS3. The bits are stored as groups of related bits and an
error flag is provided for each group to indicate when a
transmission error has been detected in one or more of the
bits in the group.
WSS data is only acquired when the TXT8.WSS ON bit is
set. Bit TXT8.WSS RECEIVED is set by the hardware
whenever WSS data is acquired. The flag can be reset by
writing a logic 0 into the SFR bit.
22.1.9
The US Closed Caption data is transmitted on line 21
(525-line timings) and is used for Captioning information,
Text information and Extended Data Services. Full details
can be found in the document “Recommended Practise for
Line 21 Data Service EIA-608” . Closed Caption data is
only acquired when bit TXT21.CC ON is set.
Two bytes of data are stored per field in SFRs. The first
byte is stored in CCDAT1 and the second byte is stored in
CCDAT2. The value in the CCDAT registers is reset to
00H at the start of the Closed Caption line defined by
CCLIN.CS<4:0>. At the end of the Closed Caption line, an
interrupt is generated if IEN0.ECC is active.
The Closed Caption data is software-processed to convert
it into a displayable format.
VPS
15 16
byte 14
VPS
WST
WSS
C
LOSED
17 18
ACQUISITION
ACQUISITION
byte 15
VPS
C
APTION ACQUISITION
19 20
byte 4
VPS
SAA567x; SAA569x
21 22
byte 5
VPS
MBK964
Objective specification
23