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2.3
2.4
2.4.1
Siemens AG
ICM CP
Screen, touch panel
Most pages in the World Wide Web are 800 pixels wide. To show a picture always at
full width, the SIMpad SL4 has an 8.4" screen with SVGA resolution (800 x 600 pixels).
This is a screen with TFT technology, which gives a flicker-free and smear-free picture
with higher colour saturation.
Controlling the illumination unit (BLI) makes practically continuous adjustment of the
screen brightness possible. The software allows the user to choose from 7 illumination
levels (see 5.4.13.5).
An 8.4" 4-wire analog resistive touch panel is fitted over the screen. The touch signals
are analysed by the A/D converter (see 2.1).
Memory
Organisation of memory
The division and organisation of memory is shown in Fig. 2 . The memory consists of
two parts:
•
32MB flash memory (read, restricted write, no execution in place)
•
64MB SDRAM (read, write, execution in place)
The flash memory retains the data even without a power supply. It contains the Image
with the operating system (OS) and the standard programs in compressed form
(configuration programs, Pocket Word etc.), as well as the persistent memory
(Persistent storage file system, Persistent registry) and the Bootloader/BOST.
The flash memory allows for a maximum 5000 write procedures. Therefore it must not
be used as a hard-disk-like memory for data files.
The remaining RAM (approx. 60 MB) is divided into Object Store and Program
Memory. Data (texts, images, parameters etc.) which is used by the executed
programs is stored in the Object Store. This is also used as a RAM file system, in
which additional programs which have been downloaded from the Internet or loaded
via the serial interface can be stored.
On initial start (see 5.2.3) of the SIMpad SL4, required parts of the operating system
and standard programs are decompressed and transferred to the RAM by the Dial-up
Bootloader (boot from flash). This safes a lot of memory space in RAM which can be
used for the Object store and the Program Memory.
The Program Memory is the working memory for executing programs. Additional
programs which are already stored in the Object Store must be copied to the Program
Memory to be executed, and therefore require twice the RAM of their size.
The user can choose the division of the remaining memory into Object Store and
Program Memory (see 5.4.13.15). The Object Store must have a minimum size, even
if no additional programs are loaded, because this part is also used for data of
standard programs and the operating system.
The Persistent Storage file system cannot be used for storing data in the flash
memory, since extra software is required for this purpose.
Technical Description
SIMpad SL4
Version V2.0
12/74
20.08.01, David Brunner
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