Touch Screen Calibration Problem.

[ikassma]

@Martin KJELDSEN​ 

I previously succeeded in Touch Screen Calibration with the help of martin KJELDSEN.

I think there is a problem while configuring the Touch Screen Calibration routine for product launch. My symptoms are as follows.

1. If TouchCalibration :: setCalibrationMatrix is executed before the first TouchGFX Task is operated, the correct value is entered.

2. If TouchCalibration :: setCalibrationMatrix is executed for Touch Screen Calibration during TouchGFX Task operation, a problem occurs in the coordinate values. For example, if you touch 400,240 points, an offset of about 60 pixels occurs in the y-axis or x-axis.

Question 1. When performing TouchCalibration :: setCalibrationMatrix, shouldn't the TouchGFX Task work ???

Question 2. What is the essential procedure when performing TouchCalibration :: setCalibrationMatrix ???

[ikassma]

Question 2. ​For example, constraints that setCalibrationMatrix should not be called when the touchGFX GUI Task is running.

[Martin KJELDSEN]

Q1: Yes, is your calibration matrix correct? I think i heard someone else have similar issues with a 4.13.0 - He ended up using his own calibration routines. I haven't investigated why this might be an issue.

Q2: setCalibrationMatrix should only be called once. The TouchGFX Engine will, after getting touch coordinates, apply the coordinate transformation automatically.

[ikassma]

To solve this problem, I applied TEST by applying only power (3.3v) to the touch screen. It was found that the voltage of the touch screen changes rapidly when dragging on the resistance touch screen and applying a little more force. I changed the Touch Screen to another product and solved this problem. I think my case is different from someone who had a similar problem with me.