Enterprise Name: Shenzhen Oric Electronics Co., Ltd.
Tel: +86-755-85276665
Mobile phone: +86-18924648655
Mailbox: Lisa@oriclcd.com
Fax: 0755-89480065
Office Address: 4th floor, Building B, No.48th,
Huanguan Middle Road, Guanhu street,
Longhua District, Shenzhen, China 518110
The Storage Method of Chinese Character in OLD LCD Display A Brief Talk on LCD Display Manufacturer
1 LCD Module Displaying Chinese Characters
Graphic LCD module is used to display Chinese characters and graphics in lattice form. Every 8 points make up one byte, each point is represented by a binary bit, and a bright spot is displayed on the screen when the point stored in 1 is displayed; the point stored in 0 is not displayed on the screen, and the commonly used 16 *16 Chinese character dot matrix is composed of 32 bytes. Taking T6963C, a widely used LCD driver controller in China, as an example, the 16*16 dot matrix font of "Guo" character is displayed in Fig. 1. 32 byte values corresponding to the right-hand font of Fig. 1 can be obtained by extracting the font of "Guo" character in the way of left-hand, right-hand and top-down by the font extraction software. By writing these bytes into the display buffer of the LCD controller in a certain order, the 16 *16 character "Guo" can be displayed on the LCD screen. Similarly, a 24*24 Chinese character needs 72 bytes, which is stored as shown in Table 1. Chinese characters of other specifications are stored by analogy.
Typical Interface Circuit of LCD Controller
The extracted Chinese characters are input into the LCD controller by a single chip computer, and the required Chinese characters can be displayed on the LCD module display screen according to the settings. Figure 2 is a typical interface circuit between LCD module and MCU. In the figure, 8051 single chip computer which is widely used in our country is chosen as MCU, 12864 (128 *64) LCD module is used, and the built-in LCD driver controller is T6963C of Toshiba Company of Japan. In the circuit, the address line A12-A15, WR and RD signals are decoded by GAL16V8 to the chip selection signal of the chip. The LCD decoding address is 0xE000, which connects the address line A0 with the C/D of the LCD control port. LCD controller receives data when A0 is low and command code when A0 is high. Therefore, the LCD data port address is 0xE000, and the LCD command port is 0xE001. Keil C51 is used for programming. The following definitions can be made in the program:
# define XBYTE ((unsigned char volatile XDATA *) 0)
# define Lcd_Data XBYTE [0 *E000]// LCD data port
# defineLcd_Code XBYTE [0*E001]//LCD command port
The data line of MCU is connected with the data port of LCD controller through 74HC245 bidirectional buffer. The selected signal/LCD_CS of LCD controller is used as the enabling signal of 74HC245. The write signal/WR of MCU controls the direction of data transmission. When the WR is low, the MCU data is written into the LCD controller; when the WR is high, the CPU reads the data and status of the LCD controller.
3. Storage and extraction of Chinese character fonts
According to the program storage capacity and addressing space of single-chip computer, the following three ways can be adopted to store the font in single-chip computer system.
The extracted Chinese character font data is stored in the program storage area as a constant array. This method is commonly used, aiming at the situation that the program is not big or the MCU does not have the function of expanding the data storage area externally.
