Mity CPU Platforms » MityDSP-L138 (ARM9 Based Platforms)

I found out that we cannot use the touchscreen whenever the mouse/keyboard is attached to the USB port.
after I plug off those, the touchscreen is working.

However, i got another issue, the ts_calibration is working with the following result.
however, I cannot use the touchscreen when I use my QT program. somehow the point I touch is shifted/deviated to a random place

root@mityomapl138:~/lcd-lx16# ts_calibrate
xres = 480, yres = 272
Took 1 samples...
Top left : X = 891 Y = 3516
Took 1 samples...
Top right : X = 816 Y = 526
Took 1 samples...
Bot right : X = 2969 Y = 483
Took 1 samples...
Bot left : X = 3011 Y = 3564
Took 9 samples...
Center : X = 1947 Y = 1989
492.043213 0.000106 -0.125147
15.992462 0.080493 -0.001538
Calibration constants: 32246544 6 -8201 -1048082 5275 -100 65536

please find the attached code for my dummy QT program

Heres some pages I would read. http://processors.wiki.ti.com/index.php/How_to_Recalibrate_the_Touchscreen

http://processors.wiki.ti.com/index.php/Tslib
Note this page mentions a ts_test program. Lets see if the calibration works when using this test app.

Note before starting the Qt gui it might be necessary to define the following variables.

export TSLIB_TSEVENTTYPE=INPUT
export TSLIB_FBDEVICE=/dev/fb0
export TSLIB_TSDEVICE=/dev/input/event0
export TSLIB_CALIBFILE=/etc/pointercal
export TSLIB_CONFFILE=/etc/ts.conf
export QWS_MOUSE_PROTO=tslib:/dev/input/event0

/home/root/gui -qws &

Thanks Jonathan for your reply,

I have follow you guidance. it improve the LCD touchsceen response. However, it's still hard to be used.
Do you have recommendation on capacitive touchscreen that supported by Critical link?

regards,

Andri Haryono wrote:

Thanks Jonathan for your reply,

I have follow you guidance. it improve the LCD touchsceen response. However, it's still hard to be used.
Do you have recommendation on capacitive touchscreen that supported by Critical link?

Hmm we've used several different cap touchscreens over the years though I'm only aware of ones we've used on the 335x. However they've all been i2c based so the L138 should be a problem.

I don't recall what the touchscreens were or where they were purchased from. I'll have to get some feedback from some other engineers. Note that when you do pick out a cap touchscreen, make sure to check for existing drivers. The few I've dealt with have required some manual rewriting of the drivers to get to work based on datasheets that are mostly in Chinese.

Jonathan Cormier wrote:

Hmm we've used several different cap touchscreens over the years though I'm only aware of ones we've used on the 335x. However they've all been i2c based so the L138 should be a problem.

*shouldn't be a problem