HD66787 Datasheet, PDF (73/159 Pages) Renesas Technology Corp – 528-channel, One-chip Driver with 262,144-color Display RAM and Power Supply Circuit for Low-temperature Poli-Si TFT (LTPS-TFT) Panels with Incorporat

HD66787
Preliminary
Interface Specifications
The HD66787 incorporates a system interface to make settings for instructions, and an external display
interface to display moving pictures. By selecting an optimum interface for display (moving or still picture,
or both), data are transmitted efficiently.
The external display interfaces are RGB-I/F and VSYNC-I/F. Through these interfaces, the data can be
updated without flickering the moving picture on the display.
In the RGB-I/F mode, the display operation is performed in synchronization with the signals (VSYNC,
HSYNC, and DOTCLK). The display data are written according to the values of the data enable signal
(ENABLE), data valid signal (VLD) and PD17-0 bits in synchronization with VSYNC, HSYNC, and
DOTCLK signals. The display data are written to GRAM to reduce the data transmission to minimum, i.e.
only when the displays are being updated. With the window address function, only the RAM area used for
moving picture display is overwritten, and therefore the simultaneous display of moving picture area, which
is overwritten, and the RAM data in the area other than the moving picture area, which is not overwritten, is
possible. In the RGB and VSYNC interface modes, write data to GRAM in the high speed write mode
(HWM = 1) while displaying moving pictures to make an access to GRAM in high speed with low power
consumption.
In the VSYNC interface mode, internal display operations are synchronized with the frame-synchronizing
signal (VSYNC). By writing data in synchronization with the falling edge of VSYNC at a fixed speed to
GRAM through a system interface, it enables moving pictures display with a system interface. In this case,
there are some constraints in the RAM writing speed and method.
The HD66787 handles the following 4 operational modes for the type of display. The setting can be made
through an external display interface. A transition between the modes must follow the transition flow.
Rev.0.22, May.23.2003, page 73 of 159