Epson S1D13705 Computer Monitor User Manual


 
Epson Research and Development Page 77
Vancouver Design Center
Hardware Functional Specification S1D13705
Issue Date: 02/02/01 X27A-A-001-10
12 SwivelView™
Many of todays applications use the LCD panel in a portrait orientation. In this case it
becomes necessary to “rotate” the displayed image by 90°. This rotation can be done by
software at the expense of performance or, it can be done by the S1D13705 hardware with
no CPU penalty.
There are two SwivelView modes: Default SwivelView Mode and Alternate SwivelView
Mode.
12.1 Default SwivelView Mode
Default SwivelView Mode requires the SwivelView image width be a power of two, e.g. a
240-line panel requires a minimum virtual image width of 256. This mode should be used
whenever the required virtual image can be contained within the integrated display buffer
(i.e. virtual image size 80K bytes), as it consumes less power than the Alternate
SwivelView Mode.
For example, the panel size is 320x240 and the display mode is 8 bit-per-pixel. The virtual
image size is 320x256 which can be contained within the 80K Byte display buffer.
Default SwivelView Mode also requires Memory Clock (MCLK) Pixel Clock (PCLK).
The following figure shows how the programmer sees a 240x320 image and how the image
is displayed. The application image is written to the S1D13705 in the following sense:
A–B–C–D. The display is refreshed by the S1D13705 in the following sense: B-D-A-C.
Figure 12-1: Relationship Between The Screen Image and the Image Refreshed by S1D13705 in Default Mode
256
256
image seen by programmer
= image in display buffer
320
SwivelView
window
320
240
AB
C
D
D
C
B
A
240
start
address
SwivelView
window
display
E
E
image refreshed by S1D13705
start
address
physical
memory