Overview

The LC74736PT is an on-screen display CMOS IC that displays characters and patterns on a TV screen under the control of a microcontroller.

For QVGA display, the LC74736PT supports the use of both a 16 × 16 dot character font and a 16 × 16 dot graphic font with 16 colors.

For WVGA display, the LC74736PT supports the use of both a 24 × 32 dot character font and a 24 × 32 dot graphic font with 16 colors.

The LC74736PT can also implement extremely varied displays by the use of an external ROM.

The LC74736PT supports both QVGA (480×234) and WVGA (800×480).

Features

(1) Screen structure

   Main: 2 screens (1 screen for WVGA display)

      30 characters×15 lines (up to 450 characters) on a QVGA panel

      33 characters×15 lines (up to 495 characters) on a WVGA panel

      (Up to 34 characters×18 lines)

   Wallpaper display screen:

      QVGA mode: maximum Permanent repetition of a 4×4 (horizontal×vertical) character pattern

      WVGA mode: maximum Permanent repetition of a 2×2 (horizontal×vertical) character pattern

(2) Character structure

   QVGA mode: About 9MHz

      16 dots (horizontal) ×16 dots (vertical): Character display

      16 dots (horizontal) ×16 dots (vertical): Graphic glyph display

   WVGA mode: About 33.2MHz

      24 dots (horizontal) ×32 dots (vertical): Character display

      24 dots (horizontal) ×32 dots (vertical): Graphic glyph display

   Character display clock:

      LC oscillator (about 10MHz)

      External clock signal input (up to 40MHz)

      Built-in PLL (VCO) (7 to 40MHz)

(3) Number of characters

   QVGA mode

      Up to 16384 characters when an external 16-bit 16M ROM is used.

   WVGA mode

      Up to 4096 characters when an external 16-bit 16M ROM is used.

         No internal ROM

         Internal character RAM QVGA: 4 characters, WVGA: 1 character

(4) Character sizes: Four horizontal sizes (1×, 2×, 3×, and 4×)

                         Four vertical sizes (1×, 2×, 3×, and 4×)

                         (The character size is specified in line units.)

(5) Display start positions: 1024 positions in the horizontal direction and 512 positions in the vertical direction.

   Setting units: Horizontal: 1 dot (in screen units)

                     Vertical: 1 dot (in screen units)

(6) Display functions

   • Blinking specification (in character units)

      Period: 1/64, 1/32, and 1/16 of the vertical sync signal (in screen units)

      Duty: Fixed at 50%

   • Box (raised or recessed) display

      Raised/recessed specification (in character units)

      Left: Off/on specification (in character units)

      Right: Off/on specification (in character units)

      Top: Off/on specification (in character units)

      Bottom: Off/on specification (in character units)

   • Border specification (in line units): Only valid with glyphs from the character font.

(7) Color specification

   Character

      • Character color (in character units): 1 of 16 colors can be specified.

      • Character background color (in character units): 1 of 16 colors can be specified.

      • Border color (in line units): 1 of 16 colors can be specified.

   Graphic

      • 16 types can be specified by ROM data

   Graphic 2

      • 16 types can be specified by ROM data

        1 color type can be changed.

   Graphic 3

      • 16 types can be specified by ROM data

        1 color table type can be changed.

      • Box (raised or recessed) color (line units): 1 of 16 colors can be specified.

      • Background color (screen units): 1 of 16 colors can be specified.

(8) Color table (palette)

   • Sixteen colors can be selected from a set of 4096 colors (One of which is specified to be transparent.)

   • Number of color tables: 4. This allows up to 64 colors to be displayed at the same time.

(9) Wallpaper screen (Graphics glyphs only)

   Wallpaper display: Repeated display under the main screen

      (up to 4 characters horizontally by 4 characters vertically).

   Sprite character display: Displayed above the main screen

      (up to 4 characters horizontally by 4 characters vertically).

(10) Line spacing control

   0-15 scan lines (in line units)

(11) Output

   Analog RGB output( to 20MHz)

   Digital RGB output (4 bits per color)

   BLK (OSD display period signal)