 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Pocket PC Forum / Developers / Platform Builder / July 2008weird touch screen and usb problem
Hello, on WinCE 5.0 I have a touch screen driver and it appears to be working just fine, I run calibrate and I can click, double click, etc,etc... as soon as I plug in a USB device the calibration goes out, and the stylus touch points are messed up. When I remove the USB device it returns back to correct calibration, If I recalibrate when the device is plugged in it work fine until I unplug the device. At first I thought it was HID devices (usb mouse and kbd) but I can plug in a mass storage device (thumb drive) and the same think occurs ? This seems pretty strange ? Any help greatly appreciated. Thanks, Joe W Or is it possible a IRQ issue? Due to some unkown reason the USB and your touch is using the same SYSINTR or an improper OAL design cause the SYSINTR of USB will mask out the IRQ of your touch panel. > Hello, > [quoted text clipped - 11 lines] > > Joe W Some kind of environmental condition? Something getting warm when USB plugged in (touch panels are analog and calibration changes with temperature).  SignatureDean Ramsier - eMVP BSQUARE Corporation > Hello, > [quoted text clipped - 11 lines] > > Joe W There are a lot of possible causes of this, the first two responses are good possibilities. Here's a third - relative driver thread priorities between your USB driver and your touch driver. Make sure your touch driver IST thread priority is high enough and that any code in the touch driver requiring timing-sensitive communication with your touch controller are protected against long periods of interruption that would cause loss of data between the driver and the controller. Tom >Hello, > [quoted text clipped - 11 lines] > >Joe W Hi... I faced the exact problem earlier. My usb stops working as soon as i touch my touchscreen. Finally, i found that was the problem with the Interrupt Control Mask register(I used pxa255), which is masking the usb interrupt as soon the touch screen is touched. Working around in this area may give a solution to your problem... SignatureRamesh.c Innovate Sofware Solutions. Bangalore. > Hello, > [quoted text clipped - 11 lines] > > Joe W Hi All, I've read all the advice and looked into the sysIntr , and IRQ and this seems to be ok there. I have just found that if I enable some debug and touch the 0,0 location on the screen I see that as a queuing point. when I plug in a usb device I see the same coordinates sent up as 166, 0. I had thought the screen coordinates would basically be static once powered up, so I was surprised to this ? I am going to start looking at how the touch driver gets the initial screen info , but if anyone could help, please do. I also notice that this does not happen if I plug a USB kbd in, but does happen it its a thumb drive or a mouse.. (I think the kbd might be a USB 1.1 device, but not sure how this plays into the problem) Thanks, Joe W. > Hi... > [quoted text clipped - 28 lines] >> >> Joe W Both Mouse and Kbd are defined in USB HID class and only using Low Speed for transportation (1.5Mb/s) mode. Due to the natural of the mouse, it might transfer more data than Kbs (people may only type couples keystroke per second, but a mouse moving could produce dozens of co-ordination in the same period), IRQ and/or the electrical signal interference could be a possible in this case. > Hi All, > [quoted text clipped - 48 lines] >>> >>> Joe W Hi All, Just thought I would follow up with the fix. It turns out that the smoothing caps on the 4 wire's from the touch screen were connected to chassis ground and not the analog ground of the touch chip. This would cause some type of signal interference and cause the readings to be incorrect. Thanks for all your help, Joe Welfeld > Both Mouse and Kbd are defined in USB HID class and only using Low Speed > for transportation (1.5Mb/s) mode. [quoted text clipped - 56 lines] >>>> >>>> Joe W |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.