hd66789 Renesas Electronics Corporation., hd66789 Datasheet - Page 84

• Manufacturer Part Number: hd66789
• Description: 528-channel, One-chip Driver For Amorphous Tft Panels With 262,144-color Display Ram, Power Supply Circuit, And Gate Circuit
• Manufacturer: Renesas Electronics Corporation.

HD66789
VSYNC Interface
The HD66789 incorporates a VSYNC-I/F, which enables moving picture display with only a system
interface and the frame-synchronizing signal (VSYNC). This interface enables moving picture display with
minimum modification to a conventional system.
The VSYNC-I/F becomes operable by setting DM1-0 = 10 and RM = 0. In the VSYNC I/F mode, the
internal display operations are synchronized with VSYNC. By writing data to RAM through a system
interface in a speed that is higher for more than a fixed speed than the internal display operation speed, it
enables moving picture display through a system interface, while preventing flickers while the screens are
being updated.
Display operations are executed by the internal clock generated by the internal oscillator and VSYNC input.
All display data are stored in RAM. This enables moving picture display only by transmitting data that are
written over, thereby minimizing the number of data transmission while displaying moving picture. The
high-speed write mode (HWM = 1) enables RAM access in high speed with low power consumption.
Rev.0.12, May 09 2003, page 84 of 156
synchronization with
Display operation in
the internal clock
system interface
RAM write via
VSYNC
Moving picture data transmission through VSYNC interface
Updating screen
Note: Data must be written in the high-speed write mode (HWM = 1) in VSYNC-I/F mode.
LCDC/
MPU
VYSNC interface
16
VSYNC
DB17-10, 8-1
CS*
RS
WR*
Updating screen
HD66789
Preliminary