February 1995

21

Philips Semiconductors

Preliminary specification

One page Economy Teletext/TV

microcontroller

SAA5290

TXT5 - Teletext register 5 (WRITE only)

BKGND OUT

Background colour displayed outside teletext boxes (logic 1).

BKGND IN

Background colour displayed inside teletext boxes (logic 1).

COR OUT

COR output active outside teletext boxes (logic 1).

COR IN

COR output active inside teletext boxes (logic 1).

TEXT OUT

Text displayed outside teletext boxes (logic 1).

TEXT IN

Text displayed inside teletext boxes (logic 1).

PICTURE ON OUT

Video picture displayed outside teletext boxes (logic 1).

PICTURE ON IN

Video picture displayed inside teletext boxes (logic 1).

TXT6 - Teletext register 6 (WRITE only)

−

This register has the same meaning as TXT5 but is only invoked if either newsflash (C5) or the

subtitle (C6) bit in Row 25 of the basic page memory is set.

TXT7 - Teletext register 7 (WRITE only)

STATUS ROW TOP

Display Row 24 below (logic 0) or above (logic 1) teletext page.

CURSOR ON

Display cursor at location pointed to by TXT9 and TXT10 (logic 1).

CONCEAL/REVEAL

Display characters in areas with the conceal attribute set (logic 1).

TOP/BOTTOM

Display Rows 0 to 11 (logic 0) or 12 to 23 (logic 1) when the double height bit is set.

SNG/DBL HEIGHT

Display each character at twice normal height (logic 1).

BOX ON 24

Enable teletext boxes in memory Row 24 (logic 1).

BOX ON 1-23

Enable teletext boxes in memory Rows 1 to 23 (logic 1).

BOX ON 0

Enable teletext boxes in memory Row 0 (logic 1).

TXT8 - Teletext register 8 (WRITE only)

CVBS0/CVBS1

CVBS0 input (logic 0) or CVBS1 (logic 1) inputs used for teletext.

TXT9 - Teletext register 9 (WRITE only)

CLEAR MEMORY

Write 20H into every location in teletext memory (logic 1).

A0

Access basic page memory (logic 0) or extension packet memory (logic 1) with TXT11 SFR.

R0 to R4

Memory row to be accessed with TXT11 SFR.

TXT10 - Teletext register 10 (WRITE only)

C0 to C5

Memory column to be accessed with TXT11 SFR.

TXT11 - Teletext register 11

D0 to D7

data byte written to, or read from, teletext memory.

REGISTER

FUNCTION