BeagleBone Black Rev C. with 4DCape-70T Resistive Touch Display


I am developing a QT5 Application with above named Display. The Application does require some GPIO’s and CAN. I’ve got some issues

  1. Unfortunately the Dispaly does use both CAN-Pins (P9.19/20 I2C for Cape identification and P9.24/26 as gpio interrupt for the Touch controller). I have not been able to relocate neither the gpio interrupt nor the i2c initialization. My current solution is using an analog signal switch controlled by a gpio which switches the i2C initialization pins (p9.19/20) to my can device during runtime. Thats a bit hacky but it works. Another soultion would be preferred though.

  2. The bootup / touch initialization needs quite some time. The touchscreen does not work for about 15-20 seconds after my application started. I can’t find the reason. 4dsystems only says that a calibration tool is started after bootup. Which service is responsible for the touch initialization and how can I reduce time?

That’s a known issue, the community hasn’t discovered it’s cause or fix for it yet… It’s either a delay in entry, or an xorg delay, or a module waiting to load…

This is the tool, GitHub - tias/xinput_calibrator: A generic touchscreen calibration program for X.Org it hasn’t been updated in some time…