TFT Character LCD Modules

○ TFT6758 interface circuit
TFT LCD Display interface circuit using the PACK plate form connected to the board, the interface definition is shown in Figure 1. TFT6758 LCD module RESET pin is connected to the J1 connector on the LPC2292 P0.22 control the LCD module reset. TFT6758 LCD module CS, WR and RD pins are connected to the J1 connector on the motherboard LPC2292 chip select, write, and read the signal connection. RS pin is used to connect the A1, when A1 is high for the data manipulation, or when A1 is LOW when the command (index) operation, i.e. to use two different addresses to distinguish between sent to TFT6758LCM LCD module command to send data . TFT6758 LCD module chip-select signal: LCM_nCS0; 0x83200000 to 0x833FFFFF; index / operation of the instruction address: 0x8320000; data manipulation Address: 0x83200002.

TFT6758 LCD module backlight LED backlight, four white LEDs connected in series, so the design of the step-up circuit, CAT32TDI is specifically used to boost white LED driver chip that can drive 4 white LEDs in series. CAT32TDI Close control pin for the output connected by the LEDC signal control (with the motherboard LPC2292 PWM pin P0.21, can use the PWM control backlight brightness), in order to ensure LEDC connected to the I / O is not configured to output can be lit LED backlight, so pick up a 10k pull-up resistor R1. CAT32TDI chip constant current output, the output is controlled by R2.

○ TFT6758 Controllers
The module is TFT6758LCD dot-matrix LCD can display graphics, characters, and a variety of symbolic information, can provide the system with a friendly interface. Which is mainly for the staff and the monitoring information is displayed, so that staff can monitor the operation clearly. TFT6758 LCD module screen size is 2.2in point pixels to 240 x 320 internal LCD controller and LCD driver supports true color 262K colors, gorgeous user interface. Module TFT6758LCD working voltage of 3.3V, inside with white LED backlight directly using 8-bit, 16-bit or 18-bit bus connected to the controller.

○ TFT6758 display principle
LCD display font data is closely related to to display subroutine reads the corresponding font data is sent to the LCD, and received by the LCD matrix in the corresponding position on the display. But the basic font data generation procedures regardless of the contents of the font data only. Chinese characters sent to the LCD must extract the font software converted into dot matrix array, can be used in the program. Text display mode, the LCD screen is 8 × 8 dot matrix display information management unit, called a text display units, each text display the corresponding text in the display buffer eight contiguous memory locations. Write text display buffer character codes, dot matrix status information (8 × 8) matrix stored in RAM. Kanji ships to describe using a 16 × 16 dot matrix, it is divided into four 8 × 8 dot matrix, to describe a character with a character code, based on the positional relationship of these four parts of the code written to the corresponding The text display buffer.

TFT LCD Module on each LCD pixel consists of integrated subsequent thin film transistor to drive. TFT LCD has a screen response speed, contrast, brightness, viewing angle, color and other characteristics.