SAA5249GP/E PHILIPS [NXP Semiconductors], SAA5249GP/E Datasheet - Page 22

• Manufacturer Part Number: SAA5249GP/E
• Description: Integrated VIP and Teletext with Background Memory Controller IVT1.1BMCX
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
IVT1.1BMCX page memory organization
The organization of the page memory is illustrated by Fig.11. The IVT1.1BMCX provides an additional row as compared
with first generation decoders; this brings the display format up to 40 characters by 25 rows. Rows 0 to 23 form the
teletext page; Row 24 is the extra row available for software generated status messages and FLOF/FASTEXT prompt
information.
1996 Nov 07
Integrated VIP and Teletext with
Background Memory Controller
Fig.12 Organization of the extension memory.
PACKET X / 24 if R0D7 = 0
PACKET X / 27 / 0
PACKETS 8 / 30 / 0 to 15
7 characters
for status
page information
MBA275 - 2
10 bytes for
7
received
10
Fig.11 Basic page memory organization.
ROW
PACKET X / 24 STORED HERE IF R0D7 = 1
1
0
1
2
24 characters from page header
rolling when display page looked for
written by IVT hardware
alphanumerics white for normal
alphanumerics green when looking
MAIN PAGE DISPLAY AREA
fixed character
by microcontroller
PACKET X / 22
PACKET X / 23
free for use
14 bytes
14
22
24
for display page
R
Row 0
Row 0 is for the page header. The first seven columns
(0 to 6) are free for status messages. The eighth is an
alphanumeric white or green control character, written
automatically by IVT1.1BMCX to give a green rolling
header when a page is being looked for. The last eight
characters are for rolling time.
Row 25
The first 10 bytes of row 25 contain control data relating to
the received page as shown in Table 5. The remaining
14-bytes are free for use by the microcomputer.
EMARK TO
Fig.11
always rolling
8 characters
(time)
MBA274
8
ROW
20
21
22
23
24
25
to
0
1
2
3
4
5
Preliminary specification
SAA5249