1997 Jul 07
22
Philips Semiconductors
Preliminary specification
Economy teletext and TV microcontrollers
SAA5x9x family
Teletext Register 0 (TXT0) - WRITE only
X24 POSN
DISPLAY X24
AUTO FRAME
DISABLE HDR
ROLL
DISPLAY STATUS
ROW ONLY
DISABLE FRAME
VPS ON
INV ON
(3)
store packet 24 in extension packet memory (logic 0) or page memory (logic 1)
display X24 from page memory (logic 0) or extension packet memory (logic 1)
FRAME output switched off automatically if any video displayed (logic 1)
disable writing of rolling headers and time into memory (logic 1)
display row 24 only (logic 1)
FRAME output always LOW (logic 1)
enable capture of VPS data (logic 1)
enable capture of inventory page in block 8 (logic 1)
Teletext Register 1 (TXT1) - WRITE only
EXT PKT OFF
(3)
8-BIT
ACQ OFF
X26 OFF
FULL FIELD
FIELD POLARITY
H POLARITY
V POLARITY
disable decoding of extension packets (logic 1)
data in packets 0 to 24 written into memory without error checking (logic 1)
prevent teletext acquisition section writing to memory (logic 1)
disable automatic processing of packet 26 data (logic 1)
decode teletext on VBI lines only (logic 0) or decode teletext on any line (logic 1)
VSYNC in first half of the line (logic 0) or second half of the line (logic 1) at start of even field
HSYNC input positive-going (logic 0) or negative-going (logic 1)
VSYNC input positive-going (logic 0) or negative-going (logic 1)
Teletext Register 2 (TXT2) - WRITE only
REQ3 to REQ0
(3)
SC2 to SC0
selects which page is modified by TXT3 page request data
start column at which page request data written to TXT3, page request data is placed
Teletext Register 3 (TXT3) - WRITE only
PRD4 to PRD0
page request data
Teletext Register 4 (TXT4) - WRITE only
OSD BANK
ENABLE
(4)
QUAD WIDTH
ENABLE
(4)
EAST/ WEST
DISABLE DBL
HGHT
B MESH ENABLE
C MESH ENABLE
TRANS ENABLE
SHADOW ENABLE
bank switching of OSD enabled (logic 1)
enable quad width characters (logic 1)
western languages selected (logic 0) or Eastern languages selected (logic 1)
disable display of double height teletext control codes (logic 1) in OSD boxes
enable meshing of area with black background (logic 1)
enable meshing of area with other background colours (logic 1)
set black background to transparent i.e. video is displayed (logic 1)
enable south-east shadowing (logic 1)
REGISTER
FUNCTION