HD66789 Datasheet, PDF (91/156 Pages) Renesas Technology Corp – 528-channel, One-chip Driver for Amorphous TFT Panels with 262,144-color display RAM, Power Supply Circuit, and Gate Circuit

HD66789
Preliminary
Moving picture display
The HD66789 incorporates the RGB interface to display moving pictures and RAM to store display data,
which provides the following merits in displaying moving pictures.
• The window address function enables the transfer of only data for the moving picture area.
• The high-speed write mode enables high-speed access to RAM with low power consumption
• Only transmitting data that are written over the moving picture area.
• Reduced transmission contributes to the reduction of power consumption of the entire system.
• In combination with a system interface, the still picture area, such as an icon, can be updated while
displaying moving pictures.
RAM access through system interface in RGB-I/F mode
RAM is accessible through a system interface in the RGB-I/F mode. In the RGB interface mode, data are
being written to RAM in synchronization with the DOTCLK input while the ENABLE is “Low”. When
writing data to RAM through the system interface, it is necessary to set ENABLE to “High” to stop data
write through the RGB-I/F. Setting RM = 0 allows RAM access through the system interface. When
reverting to the RGB interface mode, wait a write/read bus cycle. Then, set RM = 1 and the index to R22h
to start RAM access though the RGB-I/F. When the RAM writes through the RGB and system interface
conflicts, it is not guaranteed that the data are properly written to RAM.
The following is an example of moving picture display through the RGB-I/F and updating still picture area
through the system interface.
VSYNC
ENABLE
Updating screen
Updating screen
DOTCLK
PD17-0
Index set
Index
System interface ^R22
RM=0
Setting
of
address
Index
R22
Updating of area
other than moving
picture area
*Note 2
Setting
of
address
RM=1
Index
R22
Updating moving
picture area
Updating of still picture area * Note 1 _{Updating moving}
picture area
Note 1) In the RGB interface mode, the address is set at every falling edge of VSYNC.
Note 2) Set the address and the index (R22h) before RAM access starts through the RGB interface mode.
Note 3) In the RGB interface mode write data in the high-speed write mode (HWM = 1).
2001/01/01 00:00
Still picture area
Moving picture area
Updating Still Picture Area during Displaying Moving Picture
Rev.0.12, May 09 2003, page 91 of 156