spurious touchs on spi display

[MikeP]

When i the touchscreen on my LCD it occassionally presses somewhere else on the screen to where i have pressed.

The simulation on touchgfx works perfectly which means it isnt the code ive implemente in the virtual functions.

Only assumption is that the hardware is dodgy or the way im sensing the touch isnt correct.

if i debug the code and step through i cant replicate the issue so maybe a timing thing - i set the sampling rate to 160ms and same issue occurs.

Any one experienced similar issue?

Mike,

[Martin KJELDSEN]

Which display is it? Your own? Check the functionality of your touch driver. The touch functionality in the simulator is driven by your mouse so you can't compare.

/Martin

[waclawek.jan]

It may even be the hardware (and by that I mean the "glass") itself - especially capacitive touchscreens readily pick up external electromagnetic noise/interference and sometimes that results in spurious "touches".

There is no simple remedy or even diagnostics to this. Sometimes there's an obvious source of interference which can be mitigated e.g.a floating metal bezel, or LCD backlight driven from a noisy DC/DC converter. Some touch controllers have settings which can be tweaked. As a last resort, you can try to discriminate in software.

Of course the possibility of plain error in the driver as Martin said above still holds, too.

JW