PCA84C646 Philips Semiconductors, PCA84C646 Datasheet - Page 23

• Manufacturer Part Number: PCA84C646
• Description: Microcontrollers for TV tuning control and OSD applications
• Manufacturer: Philips Semiconductors

Philips Semiconductors
11 CHARACTER ROM
Each character font is stored in the on-chip character ROM
in a 12
to 18 (12
on the screen.
Row 0 is only used for the combination of two characters
in a vertical direction when North-west shadowing mode is
selected (for details see Section 12.4). Row 0 contains the
same bit pattern of Row 18 of the character above it. If no
combined character in vertical direction is intended for this
character, Row 0 should be filled with all zeros.
11.1
ROM is divided into two parts: ROM1 and ROM2. The
organization of the bit patterns stored in ROM1 and ROM2
and the file format to submit to Philips for customized
character sets is shown in Fig.17.
A software package (OSDGEM) that assists in the design
of character fonts on-screen and that also automatically
1995 Jun 15
handbook, full pagewidth
Microcontrollers for TV tuning
control and OSD applications
Character ROM organization
19 dot matrix. However, only elements in Rows 1
18 dot matrix) can be selected as visible dots
ROW
ROM2
ROM1
Fig.17 Font pattern stored in character ROM1 and ROM2.
: 1 0 0 0 0 0 0 0 FC 03 22 20 C2 3F 20 12 00 53 65 00 58
: 1 0 0 0 1 0 0 0 < - - -
: 1 0 0 0 2 0 0 0 < - - -
: 1 0 0 0 0 0 0 0 00 00 22 FC 03 22 20 F2 3F 01 20 55 0C 00
: 1 0 0 0 1 0 0 0 < - - -
: 1 0 0 0 2 0 0 0 < - - -
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
11 10 9 8 7 6 5 4 3 2 1 0
byte #
__ __ __ __ __ __ __ __ __ __ __ __ __
Column
0
1
2
3
DATA FOR FONT 2
DATA FOR FONT 3
DATA FOR FONT 2
DATA FOR FONT 3
4
5
6
7
23
8
0 0 0
3 F C
2 2 0
2 2 0
3 F C
2 2 0
2 2 0
3 F C
2 2 0
2 2 0
3 F F
0 0 1
0 0 1
5 5 3
5 5 2
0 0 6
0 0 C
0 5 8
0 3 0
9
generates the bit pattern HEX files is available on request.
The package is run under the MS-DOS environment for
IBM compatible PCs.
Regarding Fig.17 the following points should be noted.
1. Row 0 of each font is reserved for vertical combination
2. Binary 1 denotes visual dots.
3. ROM1 and ROM2 data files are in INTEL hex format
4. The unused last byte of each font in ROM1 must be
5. The unused last 2
6. The data bytes of the last 2 reserved fonts (Carriage
7. CS denotes Checksum.
A
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
ROM2
ROM1
of two fonts.
on a byte basis. Each byte is structured High nibble
followed by Low nibble.
filled with FFH.
the same data as held in the corresponding address in
ROM1.
Return and Space Codes) should be filled with 00H.
- - - >
- - - >
B
- - - 12
- - - 56
C
D
0 0 03
1 X 34
5 X 78
03
34>
78>
E
__
ROM1
0 0 0
2 2 0
3 F C
2 2 0
2 2 0
3 F F
0 0 1
5 5 2
0 0 C
0 3 0
FF
__
F F
F F
F F
FF
FF
F
PCA84C646; PCA84C846
CS
CS
CS
CS
CS
CS
1
2
bytes in ROM2 must be filled with
ROM2
MLB760
2 2 0
3 F C
2 2 0
0 0 1
5 5 3
0 0 6
0 5 8
3 F C
2 2 0
Preliminary specification