Summary: After a successful ts_calibration and ts_test, ts_test shows varying results after reboots.
I am connecting a beaglebone black to a 16 bpp, 4 wire touchscreen/LCD. The lcd is working beautifully, but I am having an issue with the touchscreen. I am connecting AIN0-3 directly to the up, down, left, and right pins of the touchscreen via breadboard and breakoutboard.
I can boot up a 3.8 RCN kernel with a custom device tree overlay (and also a modified 3.2 kernel), I can run ts_calibrate and ts_test and get perfect results.
The problem occurs on reboots, sometimes the results of ts_test are near perfect, sometimes they are off by a small but significant amount, sometimes it is way off. On a reboot when ts_test is off, if I run ts_calibrate then the results of ts_test are right on the mark.
I haven’t been able to make heads or tails of this, whether to focus an hardware or software.
Looking at the touch signals with a scope there is a small amount of noise that seems to increase in frequency as more is displayed on the LCD. However the calibration never seems to change once the board is booted so I do not believe that the noise is at the root of my issue.
module_raw input module pthres pmin=1 module variance delta=30 module dejitter delta=100 module linear
I’m exporting the following before running any ts_* utils:
export TSLIB_CONSOLEDEVICE=none export TSLIB_CONFFILE=/etc/ts.conf export TSLIB_CALIBFILE=/etc/pointercal export TSLIB_TSDEVICE=/dev/input/event1 export TSLIB_FBDEVICE=/dev/fb0 #export TSLIB_PLUGINDIR=/usr/lib/ts export TSLIB_PLUGINDIR=/usr/lib/arm-linux-gnueabihf/ts0 export TSLIB_TSEVENTTYPE=INPUT
I have a debian rootfs and I’ve installed tslibs via apt-get, but I’ve also cross compiled tslibs-1.0 and tslibs-1.1 from:
With the same results.
Any ideas/suggestions would be greatly appreciated.