S1D13704 Epson Electronics America, Inc., S1D13704 Datasheet - Page 269

• Manufacturer Part Number: S1D13704
• Description: LCD Controller
• Manufacturer: Epson Electronics America, Inc.

Epson Research and Development
Vancouver Design Center
Resource Management Issues
Description of Windows CE Display Driver Issues
Windows® CE 3.x Display Drivers
Issue Date: 01/05/24
The Windows CE 3.0 OEM must deal with certain display driver issues relevant to
Windows CE 3.0. These issues require the OEM balance factors such as: system vs. display
memory utilization, video performance, and power off capabilities.
The section “Simple Display Driver Configuration” on page 15 provides a configuration
which should work with most Windows CE platforms. This section is only intended as a
means of getting started. Once the developer has a functional system, it is recommended to
optimize the display driver configuration as described below in “Description of Windows
CE Display Driver Issues”.
The following are some issues to consider when configuring the display driver to work with
Windows CE:
1. When Windows CE enters the Suspend state (power-off), the LCD controller and dis-
2. Using off-screen display memory significantly improves display performance. For ex-
3. In the file PROJECT.REG under CE 3.0, there is a key called PORepaint (search the
a. PORepaint=0
play memory may lose power, depending on how the system is designed. If display
memory loses power, all images stored in display memory are lost.
If power-off/power-on features are required, the OEM has several options:
ample, slider bars appear more smooth when using off-screen memory. To enable or
disable the use of off-screen memory, edit the file: x:\wince300\platform\cepc\driv-
ers\display\S1D13704\sources. In SOURCES, there is a line which, when uncom-
mented, will instruct Windows CE to use off-screen display memory (if sufficient
display memory is available):
CDEFINES=$(CDEFINES) -DEnablePreferVmem
Windows CE directories for PROJECT.REG). PORepaint is relevant when the Sus-
pend state is entered or exited. PORepaint can be set to 0, 1, or 2 as described below:
•
•
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images in display memory to system memory before power-off, and add code to
restore these images after power-on.
upon power-on. Unfortunately it is not possible to instruct Windows CE to redraw
any off-screen images, such as icons, slider bars, etc., so in this case the OEM
must also configure the display driver to never use off-screen memory.
If display memory power is turned off, add code to the display driver to save any
If display memory power is turned off, instruct Windows CE to redraw all images
Ensure that display memory never loses power.
•
This mode tells Windows CE not to save or restore display memory on sus-
pend or resume.
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