saa569x NXP Semiconductors, saa569x Datasheet - Page 79

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

Philips Semiconductors
23.5.16 D
The DRC RAM is mapped into the 80C51 RAM address
space and starts at location 8800H. The character matrix
is 12 bits wide and therefore requires two bytes to be
written for each word. The first byte (even addresses),
addresses the lower eight bits and the lower nibble of the
second byte (odd addresses) addresses the upper four
bits.
For characters of 9, 10 or 16 lines high, the pixel
information starts in the first address and continues
sequentially for the required number of addresses.
Characters of 13 lines high are defined with an initial offset
of one address, to allow for the correct generation of
fringing across boundaries of clustered characters (see
Fig.36). The characters continue sequentially for 13 lines,
after which a further line can again be used for the
generation of correct fringing across boundaries of
clustered characters.
2002 May 06
handbook, halfpage
Enhanced TV microcontrollers with
On-Screen Display (OSD)
number
line
Fig.36 13-line high DRCs character format.
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
EFINING CHARACTERS
HEX
00C
0C0
C00
C00
0C0
00C
440
003
030
300
300
030
003
000
1A8
000
top left
MSB
pixel
character below
line 1 from
character above
line 13 from
bottom right
pixel
LSB
bottom line
fringing
line not used
fringing
top line
MBK975
79
23.5.17 S
CC/TXT: several special graphics characters (see Fig.37)
are provided for improved OSD effects. These characters
provide a choice of four colours within a character cell; see
Table 33. Each special graphics character uses two
consecutive normal characters.
Table 33 Special graphics character colour allocation
By default, (for backwards compatibility with the SAA55xx
family of devices) there are 16 special graphics
characters. They are stored in the character codes
8XH and 9XH of the character table (32 ROM characters),
or in the DRCS RAM.
The SAA56xx family of devices allow for 32 special
graphics characters, if TXT26.EXTENDED DRCS is set.
They are stored in character codes 8XH, 9XH, AXH and
CXH, or in the DRCs RAM, including the extended location
(64 characters).
Special graphics characters are activated when the double
plane decoding for the special graphics is set by
TXT20.OSD PLANES in single window mode or for
Page A in double window mode, or by setting
TXT29.OSD PLANES B for Page B in double window
mode.
CC: additional special graphics characters are allowed in
the CC OSD mode by enabling the Extended Special
Graphics SFR. So when TXT20.5 = 1, any character
location can be used as special graphics using bit 14 of its
parallel code (see Table 34), extended special graphic
attributes.
Remark: Fringing, underline, overline and smoothing are
not possible for special graphics.
If the screen colour is transparent (implicit in mixed mode)
and the box attribute is set inside the object, the object is
surrounded by video. If the box attribute is not set, the
background colour inside the object will also be displayed
as transparent.
PLANE 1
0
0
1
1
PECIAL GRAPHICS CHARACTERS
PLANE 0
0
1
0
1
SAA567x; SAA569x
background colour
foreground colour
CLUT entry 6
CLUT entry 7
COLOUR ALLOCATION
Objective specification