83C145 Datasheet, PDF (18/40 Pages) NXP Semiconductors – Microcontrollers for TV and video MTV

Philips Semiconductors
Microcontrollers for TV and video (MTV)
Product specification
83C145; 83C845
83C055; 87C055
13.4 Character Generator ROM
Character Generator ROM. Containing 60 displayable bit
maps, i.e. 64 minus 4, comprising:
• One for each of new line: New Line, and
• Three space characters:
– Space
– BSpace
– SplitBSpace.
Each bit map includes 18 scan lines by 14 dots.
The Character Generator ROM is maskable or
programmable along with the Program ROM to allow for
various character sets and languages.
13.5 Display RAM organization
Each Display RAM location includes:
• 6 data bits, and
• 4 attribute bits.
The 6 data bits from Display RAM, along with a
line-within-row count, act as addresses into the Character
Generator ROM. Except in special test modes that are
beyond the scope of this data sheet, Display RAM cannot
be read by the MCU program.
dbook, full pagewidth
HSYNC
VSYNC
OSD LOGIC
7
7
internal
bus
4
OSD RAM
128 × 10
ATTRIBUTE
CONTROL
6
CHARACTER
6
GENERATOR
ADDRESS LOGIC
CHARACTER
GENERATOR
60 × 18 × 14
VCLK2
VCLK1
VCTRL
RGB
DIGITAL
VIDEO OUT
VID2
VID1
VID0
MBG323
Fig.7 OSD block diagram.
1996 Mar 22
18