The LCD touch screen controller consists of the communication module, the microprocessor module and the LCD touch screen control module. The block diagram of the system is illustrated in Figure 1.
Communication module mainly includes peripherals interface such as universal serial bus (USB) and Ethernet, which enables communication between microprocessors and external devices.
Microprocessor module, as the main control unit of the whole system, mainly includes hardware layer, driver layer and application layer. It can control input and output of LCD touch screen. The hardware layer adopts the STM32F407 type micro controller, which mainly realizes the hardware circuit connection of the microprocessor control.
The driver layer includes FSMC bus driver, USB driver, Ethernet driver and serial driver, can drive the peripheral microprocessor with the external communication and the data acquisition of high data flow. The application layer mainly transplants the graphics software package emWin5.22, which can realize the design of human-computer interaction interface and the input and output control of the data.
LCD touch screen control module includes a data interface module, memory module, LCD module and touch control module, driver and driver can achieve LCD touch. Among them, the data exchange module and data signal processing is mainly based on the FSMC bus, realize the information exchange between ARM and FPGA; the memory module is mainly used for liquid crystal display data storage; liquid crystal display module mainly realizes timing control of liquid crystal display, liquid crystal display driver; touch control module is mainly used to drive ADS7843 LCD touch chip, LCD touch function.
LCD touch screen controller system workflow: microprocessor module through the communication module to collect data and send the data to the data exchange module, data exchange module for data processing and write memory module in liquid crystal display module under the control of the data from the memory module to read and complete the display; at the same time, the control module controls the touch touch chip continuously complete touch value and converting the latch value coordinate, the microprocessor module timing to the LCD touch screen control module sends a read command, directly read the coordinates of the touch operation completed.