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The handheld systems or mobile computers are
designed with touch screens for better user
friendly feature; one of the design
considerations is the power consumption for
mobile computing system with X86 system
platforms. The new South Bridge chipset of
mobile computer has built-in USB interface
only without the UART interface. In
general, the power consumption of USB
interface is higher than that of UART or
internal bus; for this reason some touch
screen controller is designed in the system
with the interface of UART or SPI, I²C or
SMBus, etc.
For Windows XP Tablet PC and Vista operating
systems, we suggest using USB interface for
touch screen controller, because Microsoft
has a USB HID descriptor definition for
touch screen device in the system.
Furthermore, Microsoft system software
utilities include some application programs
for Tablet PC, for example, pen writing,
Journal, Sticky Note, Pen Flicks, etc.,
which are user friendly for touch screen
implementations. In other Microsoft
operating systems besides Windows XP tablet
PC or Vista, touch screen will simulate
mouse device, no matter what the interface
is, RS-232 serial or USB . You could select
either one for your touch screen controller
interface at your convenience.
RS-232 interface for touch controller is
suggested if you are using DOS or Linux
system with kernel version earlier than 2.6,
for they do not fully support the USB
interface. Meanwhile, PenMount RS-232
controller can be detected from any COM
port. To make sure that PenMount will work
properly, user must correctly set the IRQ
and I/O addresses configurations of UART in
BIOS and operating systems, especially for
those other than COM1 and COM2.
However, DOS and Linux operating systems do
not have proper supports for the different
COM ports with IRQ number and I/O address;
it has to be set individually by the
technical designers or end users when using
RS-232 interface devices. We have
encountered questions from users who are
unable to have their PenMount RS232
controller functioning after installation
under DOS or Linux system but functioning
well under Windows. This kind of condition
comes from the confliction of IRQ number and
I/O address in DOS system; and COM ports
unable to start up by Linux OS. If you have
any questions on the settings, you are
welcome to contact us at
salt@salt.com.tw
or service@penmount.com .
The detailed specifications of PenMount
software driver and hardware technical
information are available on our website.
Please visit http://www.salt.com.tw and
http://www.penmount.com. |
