S3C2440 analog input function, like that STM32 without using its pins have a function like remapping some configurations, one only need to use a pin disposed in register, it is possible to use the pin AD .
Automatic (continuous) mode and a manual conversion mode conversion:
Both are for detecting a coordinate system, including X, Y and detection
Automatic continuous conversion mode only XY coordinate, detecting a merge two detected not detected at every moment.
When scribing is detected, since there is no pressing and lifting of the interrupt can not be detected every moment, which opens when the timer in the timer status detection of the touch screen, then the interrupt coordinate point conversion.
LCD and touch screen are essentially two coordinate systems in use to use the touch function, operates in the corresponding LCD, this case requires calibration coordinate system, because there is a linear relationship between the two coordinate y = kx + b
It must be obtained before using the touch screen calibration, k, b value, which is stored in the parameter area (and also prevent the next boot calibration).
The purpose of calibration: is to find the corresponding relationship, after pressing the touch screen press down, you know press in which area of the LCD.
Calibration Principle: sequentially placed in the location specified calibration point, the calibration time, the continuous reading process 16, if the hand release between, calibration values are discarded