The D8279C-5 is a Programmable Keyboard/Display Interface manufactured by NEC. This integrated circuit provides a versatile interface between a microprocessor and a keyboard or display, simplifying the design of input and output systems in various applications. It handles keyboard scanning, debouncing, and display refreshing tasks, freeing up the microprocessor for other processing activities.

Applications

• Computer Keyboards: Used to interface keyboards with computer systems.
• Industrial Control Panels: Employed in control panels for industrial equipment and machinery.
• Point-of-Sale (POS) Systems: Integrated into POS terminals for keyboard input and display output.
• Instrumentation: Used in test and measurement equipment for user input and data display.
• Embedded Systems: Implemented in various embedded applications requiring keyboard input and display capabilities.

Features

• Keyboard Scanning: Automatically scans the keyboard matrix to detect key presses.
• Keyboard Debouncing: Eliminates the effects of key bounce, ensuring accurate key detection.
• Display Refreshing: Automatically refreshes the display to maintain a stable image.
• FIFO Buffer: Includes a FIFO buffer to store keyboard input data.
• Programmable Modes: Supports various programmable modes for keyboard and display operation.
• Interrupt Handling: Generates interrupts to signal the microprocessor of keyboard input.
• TTL Compatibility: Compatible with TTL logic levels for easy integration with other digital components.

Benefits

• Simplified Interface: Simplifies the design of keyboard and display interfaces.
• Reduced Processor Load: Offloads keyboard scanning and display refreshing tasks from the microprocessor.
• Flexible Configuration: Programmable modes allow for flexible adaptation to various keyboard and display configurations.
• Reliable Operation: Debouncing and refreshing features ensure reliable keyboard and display operation.

Additional Details

The D8279C-5 typically operates on a 5V power supply and is available in a DIP (Dual In-line Package). It is compatible with various 8-bit and 16-bit microprocessors. The specific operating frequency, programming modes, and other technical specifications can be found in the official NEC datasheet for this part number. Understanding the command structure and control signals is crucial for proper implementation. It's an older part, so datasheets may be harder to find but are essential for implementation.