saa569x NXP Semiconductors, saa569x Datasheet - Page 59

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

Philips Semiconductors
22.1.6.4
The Teletext memory is divided into two banks of ten
blocks. Normally, when bit TXT1.EXT PKT OFF is logic 0,
each of blocks 0 to 8 contains a Teletext page arranged in
the same way as the basic page memory of the page
device (see Fig.19) and Block 9 contains extension
packets (applies to Bank 0 and 1), see Fig.20.
When bit TXT1.EXT PKT OFF is logic 1, no extension
packets are captured and Block 9 of both Bank 0 and 1 of
the memory are used to store two other pages.
2002 May 06
handbook, full pagewidth
Enhanced TV microcontrollers with
On-Screen Display (OSD)
(1) If ‘X24 POSN’ bit = 1.
(2) VPS data only in block 9 of either bank 0 or 1.
(3) Byte 10 reserved.
Teletext memory organisation
Basic Page Blocks (0 to 9 Bank 0; 0 and 9 Bank 1)
Row 0
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
1
2
3
4
5
6
7
8
9
0
0
OSD only
Control Data
6
7
Fig.19 Packet storage locations.
8
9
10
(3)
VPS Data
Packet X/0
Packet X/1
Packet X/2
Packet X/3
Packet X/4
Packet X/5
Packet X/6
Packet X/7
Packet X/8
Packet X/9
Packet X/10
Packet X/11
Packet X/12
Packet X/13
Packet X/14
Packet X/15
Packet X/16
Packet X/17
Packet X/18
Packet X/19
Packet X/20
Packet X/21
Packet X/22
Packet X/23
Packet X/24
59
(2)
The number of the memory block into which a page is
written corresponds to the page request number
(TXT2.REQ<3:0>) which resulted in the capture of the
page.
Packet 0, the page header, is split into two parts when it is
written into the text memory. The first eight bytes of the
header contain control and addressing information. They
are Hamming decoded and written into columns 0 to 7 of
row 25, which also contains the magazine number of the
acquired page and the PBLF flag. However, the last
14 bytes are unused and may be used by the software, if
necessary.
(1)
23
GSA071
SAA567x; SAA569x
39
Objective specification