we are using AD7877 as the touch screen controller IC in point of sale application;
The processor is i.MX6SL; we have used the linux driver for AD7877 given in ADI website.
We are observing few issue in the application-
1. we are unable to draw the signature/any image while writing fast on the touch screen.
Please find the attached image for clarity.
2. second issue is that if we press any ikon through touch screen for example "Print" the selected content is getting printed two times... looks like the function is getting invoked two times...
Pls advise with your inputs...
I'm wondering if you are aware of the AD7877 driver customization options?
Please take a look here:
AD7877 Input Touch Screen Controller Linux Driver [Analog Devices Wiki]
If you need more events/sec (waypoints) tune pen_down_acc_interval.
The stair-steps are coming from your drawing function.
Please also see the other comments/notes and other options.
Please use the eventtest utility to verify the input events.
You should get a touch event. Then a number of absolute coordinates and finally a touch release event.
Just wanted to have some more point to the second issue-
We just monitored the /PENIRQ and /DAV of AD7877... and below is the snapshot.. channel 2 is /DAV and Channel 1 is /PENIRQ... for a single /PENIRQ there is two ore more times /DAV is getting generated...Does this cause the second issue?