Are there any known issues with the TSC2004 giving spurious touch events?
We are using the DM3730 in a custom board with WinCE 6.0 and we will sporadically get fake touch events from the touch screen.
Here are things we've tried:
- Put .01uf filtering capacitors on the touch lines.
- Tried various different timing values by modifying touchscreen.cpp.
- Gone so far to even try running the TSC2004 in chip controlled mode instead of host controlled.
Some things have seemed to work better than others but we have gotten fake events with all of these. When we put an oscilloscope on the line it seems that at times the X+ (or whichever line is responsible for triggering touch detect) will start to drift instead of remain high. If it wanders low enough we get an interrupt and then we start measuring to see where we have pressed - all of this happens without anyone pressing it. If we do press it then it reads properly and if we press in the correct spot (usually lower right corner) it seems to actually help the X+ stay high when it isn't pressed - at least for a few seconds.
The touch screen we are using has worked fine for us with the iMX31 SOM - we never had a problem with fake events.
Do you guys have any idea as to what could be causing this, or any way of mitigating it - either through code or hardware changes, or both?
Thanks,
Chad