Only the lower 12 bits are valid. The upper 4 bits of the high byte are reserved or used for flags.
The GT911 is a highly integrated touch screen controller chip developed by GTCOM (Guangdong GTCOM Technology Co., Ltd.). It's designed to detect touch events on capacitive touch screens, providing a robust and reliable user interface. The GT911 supports various interfaces, including I2C, SPI, and USB, making it a versatile solution for a wide range of applications. gt911 register map
Set the : The GT911 usually defaults to 0x5D or 0x14 depending on the state of the Reset and INT pins during power-up. Only the lower 12 bits are valid