Method for interfacing single chip computer and graphic liquid crystal display
Dot matrix flat panel liquid crystal displays are widely used in various portable devices. Different manufacturers offer a variety of core liquid crystal display controllers tailored for specific applications. For instance, Hitachi’s MDF series employs integrated chips such as HD44780, HD61830, HD61202, and T6963C as the display controllers. These control chips differ in their logic circuits, command sets, and parameter specifications. However, once a flat dot matrix graphic LCD has an established control circuit, users don’t need to worry about the specific integrated chip used. For example, Hitachi's MDF series only requires understanding a few key signals from the control circuit, making it easy to integrate into development projects. The signal configuration remains largely consistent across different models, which simplifies the process.
This section focuses on the Hitachi MDF5001 160×128 dot matrix graphic LCD. It explains how to interface this display with an 8051 microcontroller and provides sample software for displaying both characters and Chinese characters. The MDF5001 uses the T6963C controller, which features a 64 KB display buffer and a 128-character dot matrix ROM. It supports both character and graphics modes, and both can be activated simultaneously.
The control signals include an 8-bit data bus (DO–D7), a write signal (WR), a read signal (RD), a chip enable signal (CE), a command/data select signal (C/D), a pause signal (HALT), and a reset signal (RESET). The C/D pin determines whether the microcontroller is sending a command or data. When reading, it controls whether the status or data is being accessed.
The display also has a set of control codes that define its operation, such as initializing the display, setting the cursor position, and clearing the screen. Additionally, there is a status word that indicates the current state of the display when the RD signal is low, WR is high, CF is low, and C/D is high. This allows the microcontroller to check if the display is ready for further operations.
In terms of interfacing with an 8031 microcontroller, the control port (CONP) is mapped to address 8000H, while the data port (DATP) is at 8001H. During initialization, the display is configured to operate in both text and graphics mode. A subroutine called LCP is used to check the display status and wait until it is ready for writing. This ensures smooth communication between the microcontroller and the LCD.
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