HD66781 Datasheet, PDF (148/196 Pages) Renesas Technology Corp – 720-channel Source Driver for a-Si TFT/Low Temperature Poly-Si TFT Panels with 262,144-color display RAM

HD66781
Preliminary
Display Synchroniaing Data Transfer
The HD66781 outputs BST signal that indicates the start of vertical retrace line period for flicker-free
screen update. The BST signal is used as trigger to start internal GRAM write so that data transfer is
synchronized with display scan.
LCDC/MPU
BST
CS*
RS ^HD66781
WR*
DB17-10,8-1
16
Display synchronizing data transfer: Interface example
By writing data to RAM through the 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 an conventional
interface and flicker-free screen update.
All display data are stored in RAM. Therefore, it only requires transfer of the data that is written over to
update the screen, thereby minimizing the numbers of data transfers while displaying moving picture. The
use of high-speed write mode (HWM = 1) with VSYNC interface enables RAM access in high speed with
low power consumption.
BST
System interface
RAM data
Write
Display
execution with
internal clock
Moving picture data transmission through VSYNC interface
Note 1) Data must be written to RAM in the high-speed write mode (HWM = 1) in VSYNC interface mode.
Rev.0.5, July.31.2003, page 148 of 196