HD66787 Datasheet, PDF (62/159 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
RAM Access through RGB-I/F and System I/F
The HD66787 writes all display data on the panels to the internal RAM. This enables the transfer of only
the data for the moving picture area as well as for the frames for updating screens through the RGB
interface. By writing data in the high speed write mode (HWM = 1) and with the window address function,
the HD66787 enables the high-speed access to RAM with low power consumption while displaying
moving pictures. In the frames other than the moving picture screen update, the display data in the area
other than the moving picture area can be updated through a system interface.
The RAM access is also possible through a system interface even in the RGB-I/F mode. In the RGB
interface mode, data are written to RAM in synchronization with the DOTCLK during ENABLE = “Low”.
When writing data in the RGB-I/F mode through the system interface, it is necessary to set the ENABLE
“High” to stop writing through the RGB interface. After accessing to RAM through the system interface,
wait an enough time for the write/read bus cycle before starting accessing to RAM through the RGB
interface. When RAM accesses through the RGB and system interfaces conflict, there will be no guarantee
that data are properly written to RAM.
VSYNC
ENABLE
DOTCLK
PD17-0
Updating
(both panels)
Updating
(both panels)
Setting of index
System interface
Index
R22
RM=0
Setting
of
address
Index
R22
Updating of area
other than moving
picture area
RM=1
Setting
of
address
Index
R22
Updating or moving
picture area
Updating still picture area*1
Updating or moving
picture area
Note 1) When RGB-I/F is selected, the address setting is made at every falling edge of VSYNC.
Note 2) The address set and the index set must be made before the RAM access throught the RGB interface.
Note 3) The high-speed write mode should be used in RGB-I/F and VSYNC-I/F modes.
2001/01/01 00:00
Still picture area
Moving picture area
Updating Still Picture Area during Displaying a Moving Picture
Rev.0.22, May.23.2003, page 62 of 159