With the rapid development of science and technology, the localization rate of broadcast television equipment is also increasing. In a high-performance broadcast television system, a user-friendly Chinese human-computer interaction interface is particularly important. This paper designs a human-computer interaction interface system for a broadcast television system. Based on meeting the display and control requirements of the "digital stereo FM modulator," it uses an MSP430F149 microcontroller as the system's MCU; the LCD screen is an LCM168651 display module that meets the requirements of displaying Chinese characters in 4 rows of 11 columns and letters in 4 rows of 22 columns; and it also meets the human-computer interaction requirements of users setting working parameters and querying working status via keyboard input. 1. System Composition This system mainly consists of three modules: the MCU with the MSP430F149 microcontroller as its core; the menu display module with the LCM168651 as its main component; and the keyboard scanning management module with the ZLG7289B as its main component. 1.1 Microcontroller Control Module The microcontroller control module in this system mainly completes the acquisition and processing of display and control information, as well as communication with other subsystems of the "digital stereo FM modulator." The selection requirements mainly consider the following aspects: • Low power consumption; • Abundant I/O ports and timing/interrupt functions; • Operating voltage of approximately 3V; • At least one serial communication interface; • More than 8KB of storage space; • Basic clock module above 4MHz; • Encryption protection function. Based on the above requirements, we selected the TI MSP430F149, an ultra-low power Flash-type 16-bit RISC instruction set microcontroller. Its main performance characteristics fully meet the design requirements. 1.2 Menu Display Module The menu display module mainly performs the real-time display function of system information and can scroll through different information under keyboard control. The "Digital Stereo FM Modulator" has the following main requirements for its display module: • Simultaneous display of at least 3 rows and 10 columns of Chinese characters; • Scrollable display of system information; • Parallel and serial interfaces, simple circuitry; • Operating voltage within 5V; • Clear display without glare, strong anti-interference capability. Our design uses the LCM168651 graphic dot matrix LCD module from Beijing Qingyun Company. This module is a passive display, less affected by external light interference, does not generate electromagnetic interference, and displays clear content with high resolution. 1.3 Keyboard Control Module The keyboard control module is an important component of the human-computer interaction interface, allowing users to set working parameters and query working status via keyboard input. The main requirements for this module in the "Digital Stereo FM Modulator" are: • Minimum of 6 keyboard keys; • Easy connection to microcontroller systems; • High reliability. Our design uses the ZLG7289B digital tube display driver and keyboard scanning management chip, designed by Guangzhou Zhouligong Microcontroller Development Co., Ltd. It can directly drive 8-digit common cathode digital tubes and scan and manage up to 64 keys. The operating voltage of both the chip and the microcontroller system can be controlled at around 3V, avoiding level mismatch issues between them. 2 System Hardware Design 2.1 System Block Diagram To facilitate understanding of the system's working principle, a system block diagram is first presented, as shown in Figure 1. Figure 1 System Block Diagram The MSP430F149 microcontroller in the system serves as the microcontroller, allocating system resources and communicating with the LCD module via a parallel bus and with the keyboard control module via an SPI serial bus. The microcontroller's program is written and debugged using in-circuit programming. The system is powered by a 5V power supply, and the system clock is 4MHz. The system's working principle can be summarized in two aspects: First, the microcontroller receives status information from the "digital stereo FM modulator" system in real time through an expansion interface. This status information is represented internally by different variables, which are then provided to the LCD module via a parallel bus to modify the corresponding display parameters, thus completing the display and updating of system information. Second, the microcontroller detects whether the keyboard control module has a control request via polling. When a control request is received, the microcontroller issues different instructions to the LCD module based on the key value to change the display content or modify system parameters. Changing the display content is equivalent to querying the working status. When modifying system parameters, the microcontroller is also responsible for transmitting the modified system parameters to the "digital stereo FM modulator" system. 2.2 LCD Display Principle The LCM168651 is a graphic dot-matrix LCD. This module integrates the LCD chip and the control chip, and its communication with the outside world is through a series of interfaces. The specific usage of this module is described below. The LCD screen is divided into 168*65 dot matrix segments. Each Chinese character occupies 16*16 dot matrix segments, while other characters or numbers occupy 8*16 dot matrix segments. Therefore, when displayed full-screen, it can display a maximum of 4 rows and 11 columns of Chinese characters or 4 rows and 22 columns of characters and numbers. Character sets for Chinese characters or other characters/numbers can be found in the national standard character set, or they can be generated individually using specialized software. This design uses the latter method. The software used is ZIMO21.EXE, which can retrieve character sets for one or more Chinese characters or other characters at once according to the user's needs. The basic operation is as follows: Invert the Chinese character image vertically and swap the first 16 bytes before and after the C51 extraction; invert the letter or number image vertically and swap the first 8 bytes before and after the C51 extraction. For example, to display the Chinese characters "广播电视" (Songti 12pt font, default setting of ZIMO21.EXE), users can directly type "广播电视" in the ZIMO21.EXE software, set "image upside down", select "C51 extraction", and the font library for the Chinese characters "广播电视" will be generated. As shown below: /*—— Text: 广——*/ /*—— Songti 12; The corresponding bitmap for this font is: width x height = 16x16 ——*/ 0x40,0x30,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFC,0x04,0x04,0x04,0x04,0x05,0x06,0x04,0x04,0x04,0x04,0x04,0x04,0x04,0x00 /*—— Text: 播——*/ /*—— Songti 12; The corresponding bitmap for this font is: width x height = 16x16 ——*/ 0x42,0x81,0x7F,0x00,0x01,0x01,0xFF,0x49,0x49,0x7F,0x49,0x49,0xFF,0x01,0x00,0x00, 0x08,0x08,0xFF,0x88,0x48,0x12,0x96,0x5A,0x32,0xFE,0x31,0x59,0x95,0x91,0x90,0x00 /＊—— Text: Electricity——＊/ /＊—— SimSun 12; The corresponding pixel grid for this font is: width x height = 16x16 ——＊/ 0x00,0x00,0x0F,0x04,0x04,0x04,0x04,0x04,0x3F,0x44,0x44,0x44,0x44,0x44,0x4F,0x40,0x70,0x00, 0x00,0x00,0xF8,0x48,0x48,0x48,0x48,0x48,0xFF,0x48,0x48,0x48,0x48,0xF8,0x00,0x00,0x00, /＊—— Text: View——＊/ /＊—— Songti 12; The corresponding bitmap for this font is: width x height = 16x16 ——＊/ The character set is created by swapping the first 16 bytes of each Chinese character's character set and storing them in a specific array `chinese[]`. The position of the first byte of each character's character set in the array is the character's index. At this point, the character set is complete. The following steps involve displaying Chinese characters at designated positions on the LCD screen: 1) Initialize the LCD module; 2) Set the screen coordinates (X, Y) of the Chinese characters; 3) Transfer the Chinese character font information to the LCD module one by one via the parallel port for display. Step 1) is completed by writing a series of command words to the LCD module; steps 2) and 3) are generally completed using custom-named functions, such as `disp_Chinese[X,Y,Number]` in this solution, where X and Y represent the screen coordinates, and Number represents the position of the Chinese character in the array. During the design process, parameters such as the font and size of the Chinese characters can be set as needed to achieve a visually appealing effect. 2.3 Keyboard Control Principle In this design, the ZLG7289B chip is mainly used in the keyboard control module. This chip can directly drive an 8-digit common-cathode seven-segment display (or 64 independent LEDs) and can also scan and manage up to 64 keys. The ZLG7289B has a simple peripheral circuit. Communication with the microcontroller system requires only three lines: CS, CLK, and DIO, a so-called SPI serial bus mode, making expansion very convenient. Debouncing measures are already implemented during keyboard scanning, so no additional debouncing code is needed in the program, making it very suitable for the needs of this design. Its basic principle is as follows: When a key is pressed, the ZLG7289B's INT pin goes low, sending an interrupt request to the microcontroller. The microcontroller can handle this either through an interrupt or by polling the /INT pin level. The key value is read promptly when the /INT pin goes low. After reading the key value, the /INT pin does not automatically return to a high level; it must wait until the key is released. If the key value is not read promptly, the INT pin will return to a high level after the key is released, and attempting to read the key value while the INT pin is high may not yield meaningful data. Keys K0 to K5 correspond to key values ​​0 to 5, and the microcontroller can perform different actions based on the key value. 3 System Software Design As mentioned earlier, the system's operation is essentially a process where the microcontroller continuously adjusts the LCD display content and transmits information based on external data. The system's software flowchart (Figure 2) is provided below, along with a detailed explanation of the system's functions and operation. [align=center]Figure 2 System Software Flow[/align] Explanation: The most important task in system initialization is to complete the setting of the basic working mode of the LCD, mainly including display bias setting, contrast setting, working clock source selection, backlight setting, etc.; Since the microcontroller system has two working clocks, namely high-frequency clock and low-frequency clock, different clock modes correspond to different setting methods, so clock initialization must be performed before use; The main display content of the display module includes "Power-on screen", "Main parameter screen", "Settings menu", 6 sets of "Setting values", 6 sets of "Preset values", "Fault indication screen" and some sub-screens; After the system is powered on, the "Power-on screen" is automatically displayed, and the display content of the power-on screen can be adjusted as needed; After the "Power-on screen" is displayed for a certain period of time (the time can be set, 30 seconds in this design), it automatically switches to the "Main parameter screen" for display; The main parameter screen displays the most important parameters of the "Digital Stereo FM Modulator" system, such as carrier frequency value, frequency offset value, incident power, reflected power, frequency setting switch status, instantaneous progress of left and right channels, etc. In the 6 sets of "Setting Values" and 6 sets of "Preset Values" menus, the "Up" and "Down" keys are used for selection. Once a menu is entered, the "Left" and "Right" keys are used for selection, and the "Up" and "Down" keys are used to change parameter values. In the "Main Parameter Screen," if there is a "Confirm" button, the system will enter the "Settings Menu." In subsequent menus, if there is no operation for a long period (adjustable time, 10 seconds in this design), the system will automatically return to the previous menu until returning to the "Main Parameter Screen." In the "Settings Menu," if there is a "Cancel" button in subsequent menus, the system will also automatically return to the previous menu until returning to the "Main Parameter Screen." In addition to basic control functions, the system software flow includes certain protection settings, such as a watchdog timer, to prevent the program from accidentally entering an infinite loop. 4. Conclusion Through experiments, it has been demonstrated that the Chinese human-computer interaction interface system designed in this paper effectively meets the display and control requirements of the "Digital Stereo FM Modulator." Because this module prioritizes scalability and upgradeability in its design, it allows for expansion and upgrades in the selection of key components and program design. Therefore, it will be well-suited for subsequent optimization and functional expansion, and can also serve as a valuable reference for the design of Chinese human-computer interaction interfaces in other broadcast television systems. The authors' innovations are: 1. A detailed design scheme for a Chinese human-computer interaction interface in broadcast television systems is proposed; 2. This method is applied to professional broadcast television systems with good results. References: 1. "Design of a Low-Power Chinese Human-Computer Interface Based on MSP430 Microcontroller", Department of Biomedical Engineering, Fourth Military Medical University, Jiao Chun, Dong Xiuzhen, Yang Guosheng, Huo Xuyang, 2006; 2. "Design of Human-Computer Interaction System Based on ARM Signal Generator", Ni Zhenhao, Lu Boyou, Tian Ze, Microcomputer Information, 2007, No. 5-2, pp. 134-136; 3. "MSP430x1xx Family User's Guide", 2000.