Poor touch screen

Go to the same machine that sells today. The phenomenon is: Click to appear in Dayton.

The reason for this analysis is: the communication speed problem of the Android board and the touch Screen main control board.

Asked rk3188 assist engineer, he said rk3188 have this bug, only 3488 have modified good ...

Workaround: Increase the frequency with which the touchscreen board accepts touch events.

Postscript

1 Capacitive screen Touch principle:

Mainly is the principle of mutual capacity, by measuring the hand touch to the screen when the TX and RX node capacitance change, establish a reasonable mathematical model to calculate the correct coordinates of the finger. The job of the software is to implement this mathematical model with the fewest resources possible (consider the chip cost). The complex parts of the model include the calculation of coordinates, the pairing of multiple coordinate points, the near-distance point splitting, the processing of large-area pressing, the fast sliding processing, the smoothing of the trajectory, and so on. In addition, because the capacitive screen is more sensitive to the external environment, but also need to add some de-noising according to the actual situation, more common interference, such as LCD interference, radio frequency interference, and rising temperature interference. Because the algorithm part involves the core technology of the manufacturer, each model is different, and there is no common case. In general, this recognition process and image processing is a bit similar, all through the algorithm to extract feature information.

2 software principle: Touch Event TouchEventRepresents an event that occurs when a touch behavior changes on a plane. TouchRepresents a point of contact between the user and the touch plane. TouchListRepresents a series of touch; This interface is typically used when the user has multiple fingers touching the touch plane at the same time. DocumentTouchContains some of the creation TouchObjects and TouchListAn easy way to object. ？？？？？ Huang always wants me to study this stuff.

Poor touch screen