Hi Group,
I pose the following dilemma and look forward to enthusiastic discussions.
As mentioned in a previous e-mail to you'll, we have developed an embedded PC with a touch screen. This device runs on a RMI, Alchemy processor (AU1250) and its touch screen is connected to this CPU via an ADS7843 chip and through the SPI bus. So far so good and pretty standard. The system originally ran on WinCE5.0 (Booooo!) and we are currently porting it to Linux.
Now the problem that we are facing is that after the first 3-4 touch events, no more touch events are recorded after that and the sensitivity of the clicks is very weak. Lastly, when the screen is touched while a video is playing the video and audio pause for the duration of the touch.
One of the reasons for why we are having problems with the screen's response, could be that the aforementioned SPI connection is multiplexed (74CBELV3257) with an on-board battery and RTC (DS1339) - see page 9 of the attached schematics.
I would really appreciate any guidance someone can give based on prior experience. Please see the schematics and the touch screen driver code for reference (http://drop.io/g8hz909). Since we are based out of Bombay we could also meet up and discuss this in further detail. Of course, we are willing to compensate high-quality assistance that leads to eventual resolution of the problem.
Thank you guys very much in advance. Have fun, Paul
On Wed, Oct 6, 2010 at 5:33 PM, Paul Schwarz paul.schwarz@enrouteinc.comwrote:
Hi Group,
I pose the following dilemma and look forward to enthusiastic discussions.
As mentioned in a previous e-mail to you'll, we have developed an embedded PC with a touch screen. This device runs on a RMI, Alchemy processor (AU1250) and its touch screen is connected to this CPU via an ADS7843 chip and through the SPI bus. So far so good and pretty standard. The system originally ran on WinCE5.0 (Booooo!) and we are currently porting it to Linux.
Which Linux distribution you are using ?Have to added the Driver properly? I guess ad7843 is Ti's Chipset and it's driver is freely available for download.
Now the problem that we are facing is that after the first 3-4 touch events, no more touch events are recorded after that and the sensitivity of the clicks is very weak. Lastly, when the screen is touched while a video is playing the video and audio pause for the duration of the touch.
How you are testing these (Touch Events), Are you trying with any
standalone application or with the Operating System features ? Which tool you are using for the Calibration of TS.
One of the reasons for why we are having problems with the screen's
response, could be that the aforementioned SPI connection is multiplexed (74CBELV3257) with an on-board battery and RTC (DS1339) - see page 9 of the attached schematics.
You cant send the files as attachment here.So provide some other source for reviewing the schematics.
--
Siji Sunny Net4uonline Pvt.Ltd Mumbai
On Wednesday 06 October 2010 17:33:33 Paul Schwarz wrote:
Hi Group,
I pose the following dilemma and look forward to enthusiastic discussions.
could you post plain old PDFs of the schematic. those flash-pdfs are a thorough pita.
As mentioned in a previous e-mail to you'll, we have developed an embedded PC with a touch screen. This device runs on a RMI, Alchemy processor (AU1250) and its touch screen is connected to this CPU via an ADS7843 chip and through the SPI bus. So far so good and pretty standard. The system originally ran on WinCE5.0 (Booooo!) and we are currently porting it to Linux.
Now the problem that we are facing is that after the first 3-4 touch events, no more touch events are recorded after that and the sensitivity of the clicks is very weak.
The input of the A-D converter is a high impedance source. In a noisy environment, the parasitic Cs charge up. This is usually the cause of gradual loss of sensitivity.
Lastly, when the screen is touched while a video is playing the video and audio pause for the duration of the touch.
this could definetly be the driver waiting for "release" event.
-
jtd -
Paul Schwarz -
Siji Sunny