Overview

The LC74794 and LC74794M are CMOS LSIs for on-screen display, a function that displays characters and patterns on a TV screen under microprocessor control. They feature a built-in PDC/VPS/UDT interface circuit. These LSIs support 12 × 18 dot characters and can display 12 lines by 24 characters of text.

Features

• Display format: 24 characters by 12 rows (Up to 288 characters)

• Character format: 12 (horizontal) × 18 (vertical) dots

• Character sizes: Three sizes each in the horizontal and vertical directions

• Characters in font: 128

• Initial display positions: 64 horizontal positions and 64 vertical positions

• Blinking: Specifiable in character units

• Blinking types: Two periods supported: 1.0 second and 0.5 second

• Blanking: Over the whole font (12 × 18 dots)

• Background color

— Background coloring: 8 colors (internal synchronization mode): 4fsc

— Background coloring: 6 colors (internal synchronization mode): 2fsc

— Blue background only: NTSC

• Line background color

— Can be set for 3 lines

— Line background coloring: 8 colors (internal synchronization mode): 4fsc

— Line background coloring: 6 colors (internal synchronization mode): 2fsc

• External control input: 8-bit serial input format

• On-chip sync separator and AFC circuits

• PDC/VPS/UDT interface circuit

• Composite video output in the PAL or NTSC format