The UPD8212D is an 8-bit input/output (I/O) port chip manufactured by NEC. This device is designed to provide a simple and efficient interface between a microprocessor and peripheral devices. It is commonly used with Intel 8080/8085 and similar 8-bit microprocessors to expand their I/O capabilities.

Applications

• Microprocessor-based control systems: Commonly found as an I/O expander in systems using 8080/8085 microprocessors.
• Parallel printer interfaces: Can be used to interface a microprocessor to a parallel printer.
• Keyboard interfaces: Used to read data from a keyboard.
• Industrial control: Controlling actuators, reading sensor data, and interfacing with other industrial equipment.
• Data acquisition systems: Providing parallel I/O for data acquisition purposes.

Features

• 8-bit I/O port: Provides 8 bidirectional I/O lines that can be configured as inputs or outputs.
• Three-state outputs: The output lines can be placed in a high-impedance state, allowing multiple devices to share the same bus.
• Input latch: An on-chip latch can be used to store input data.
• Output latch: Provides a latch for holding output data.
• Interrupt capability: Can generate an interrupt signal to the microprocessor when data is available or when an event occurs.
• TTL compatible: Compatible with standard TTL logic levels.

Benefits

• I/O expansion: Expands the number of I/O ports available to the microprocessor.
• Simplified interfacing: Simplifies the interface between the microprocessor and peripheral devices.
• Flexibility: The bidirectional I/O lines can be configured as inputs or outputs as needed.
• Efficient data transfer: Allows for efficient parallel data transfer.
• Interrupt-driven operation: The interrupt capability allows for efficient event handling.

Additional Details

The UPD8212D is typically packaged in a 24-pin DIP (Dual In-line Package). It operates from a single +5V power supply. The device is controlled by several control signals, including chip select (CS), mode select (MD), and data input strobe (DI). The mode select input determines whether the port is configured as an input or an output. The input and output latches allow for asynchronous data transfer between the microprocessor and the peripheral device.