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)