Touch Screen response time

Dec 9, 2008 at 12:46 AM
Is there any way to speed up the touch screen response time?  The Gumstix / Windows CE 6.0 system has a noticeable delay, especially when dragging, which is limiting the effectiveness of our application.  I wonder if there are some settings in the tsc2003.c driver which contribute to latency?  Or something to do with the priority of the process in the operating system?  Any way to call a high-speed driver?  We'd appreciate any hints.  Thanks for an amazing product!
Dec 15, 2008 at 1:31 PM
You mihgt try playing with the mouse properties.

DV
Dec 15, 2008 at 5:33 PM
Tried that.

We think the touch screen is asserting continuous interrupts with high priority when dragging, keeping the screen from refreshing quickly.

Screen refresh with no touch = 17 msec.
Screen refresh while dragging = 200 msec.

Is there a way to mask the touch screen interrupt (/penirq) during redraw, or modify the process priorities?

Thanks again,
Brad
Dec 15, 2008 at 6:15 PM
The touch screen chip generates an interrupt when the pen is pressed down or lifted up.
While it is down it scans at ~100 times a second.
 There are some parameters in the registry you might be able to tweek.
Remember the touch controler works through the SPI bus.
Dec 15, 2008 at 6:24 PM
The default scan time is ~1ms as stated above. I belive this can be overridden by changing the registry value:
HKLM\HARDWARE\Devicemap\Touch\
TimerIncrement


DV