VGA Controller. CL-GD620 Datasheet
PRELIMINARY DATA SHEET
• Direct interface to dual-line, dual panel LCDs
• Full backwards compatibility at the hardware level
• 256 color modes mapped to 32 gray shades on LCD
• Text & graphics scaling to fit LCD resolution
• Programmable for 8 or 16 bit PC bus interface
• Hardware graphics pointer and caret
• Fully compatible with GD510N520A VGA chipset
• Software selectable support for LCD, Plasma, EL
and digital/analog CRT displays
• Intelligent 8/16 bit Video Memory read/write
interface from the microprocessor
• Can work with multi-frequency synthesizer IC
• 32 bit non-multiplexed Video Memory interface
• Supports eight 64kx4 or eight 256kx4 DRAMs,
or four 128Kx8 pseudo-static RAMs.
• Support for system power down modes
• 16 ICs including RAM for motherboard VGA
Can share video memory & RAMDAC with
graphics coprocessor (eg 34010)
• Advanced low power CMOS technology
CL - GD 6101620
Flat Panel/CRT Enhanced
The CL-GD610 Graphics/Attributes chip and the
CL-GD620 Sequencer/CRT Controller chip are enhanced
versions of the CL-GD510A/520A VGA chipsets and
continue to be hardware compatible with the IBM® VGA,
EGA, CGA, and MDA standards, as well as with the
Hercules® HGC at all levels-register, data path and BIOS.
In additiqn, these chips may be used with a variety of flat
panel displays as well as all popular CRT displays (CD,
MD, ECD, PS/2, Variable frequency).
Monochrome LCD panels are driven by duty cycle
modulation techniques to yield 16 gray scales with no
screen flickering or stability problems. In addition,
CIRRUS LOGIC's AutoMapTM technique automatically
maps 256 colors into as many as 32 shades of gray for
CRT quality gray scale emulation. Foreground/background
color attributes are remapped automatically for maximum
contrast. Expanded Text and Graphics modes provide larger
character fonts and the ability to fill a panel (via
ratiometrically determined scanline replication) even with
low-resolution video modes. If expanded modes are not
desired, automatic screen centering is performed.
Panning/data compression allows viewing of 720 column
modes on 640 column panels.
(cont'd on next page)
80r 16 bit
2x (64K x 4) or
2x (256K x 4)
CL - GD 6101620
Operating at dot clock rates up to 33 MHz, the CL-GD610/620 chip set supports high resolution graphics and
alphanumeric display modes for both monochrome and color, and for high resolution variable frequency and PS/2
monitors. Refresh rates from 60Hz up to 160Hz are available.
CIRRUS LOGIC's proprietary technology provides greater contrast, reduced flicker, and lower power dissipation with
dual-line, dual-panel 400 or 480 scanline LCD panels.
Video outputs to CRT displays are provided in 4 bits per pixel (all resolutions) and 8 bits per pixel (256 color
modes). Using analog video output and an external palette, selection may be made from 256K colors.
Video outputs to flat panel displays are provided in dual-panel format (4 bits each to upper and lower panels). LCD
panels may be directly driven.
Plasma panels may be driven by the CRT video signals. AutoMapTM (256 color to 32 gray scale mapping) will
work with gas plasma panels that can support 16 gray shades.
The intelligent 8/16 bit Video Memory Interface detects memory map configurations that place adjacent bytes in
adjacent memory locations and automatically configures the chipset as a 16 bit peripheral. 16 bit operation may also
be configured by program control.
The CL-GD610/620 implements all control and data registers in the current graphics standards, including those of the
6845 CRT Controller. Flexible register write protect control and the ability to save/restore all registers are both key
elements enabling the chipset to be used in a variety of operating system and application environments.
The sequencer design provides more video memory cycles for the CPU during the normal video refresh/display cycle.
During display-blanked intervals, ALL memory cycles can be allocated to process CPU memory requests.
The hardware supports a mouse/graphics cursor, and a blinking insertion point text cursor. Additional text cursor
controls include blink disable and replace/invert mode control. The hardware supports simultaneous and independent
smooth scrolling of two separate text screens.
The CL-GD610/620 is designed for minimum external circuitry support and is ideal for integrated systems. For
example, only 18 chips are necessary for a low-cost controller that can drive both a 640x480 LCD panel as well as a
PS/2 monitor. No PALs are required with this duall00-pin QFP chipset.