The MSM82C55A-2R3 is a Programmable Peripheral Interface (PPI) chip manufactured by OKI/Metcal. The 82C55A is a widely used and versatile I/O expansion device that allows a microcontroller or microprocessor to interface with various peripheral devices.

Applications

• Parallel I/O ports for microcontrollers and microprocessors.
• Interface to printers, keyboards, and other peripheral devices.
• Control of external devices such as relays and motors.
• Data acquisition systems.
• Industrial control systems.

Features

• 24 programmable I/O lines.
• Three 8-bit ports (Port A, Port B, Port C).
• Three operating modes: Mode 0 (Basic I/O), Mode 1 (Strobed I/O), and Mode 2 (Bidirectional Bus).
• TTL compatible inputs and outputs.
• Low power CMOS technology.

Benefits

• Flexible I/O expansion for microcontrollers and microprocessors.
• Simplified interfacing to a wide range of peripheral devices.
• Reduced component count and board space.
• Easy to program and use.
• Low power consumption.

Additional Details

The MSM82C55A-2R3 provides 24 programmable I/O lines that can be configured as inputs or outputs. The three 8-bit ports (Port A, Port B, and Port C) can be individually programmed to operate in one of three modes. Mode 0 provides basic I/O functionality, Mode 1 provides strobed I/O functionality for handshaking with peripheral devices, and Mode 2 provides bidirectional bus functionality for interfacing with memory or other peripherals. The specific operating parameters and programming details can be found in the OKI/Metcal datasheet for this part number. The 82C55A is typically interfaced to a microcontroller or microprocessor via its address, data, and control lines.

The 82C55A is a classic and widely used I/O expansion device that has been around for many years. It is still used in many embedded systems due to its versatility and ease of use. OKI/Metcal is a reputable manufacturer of semiconductor devices.

Programming the 82C55A involves writing control words to its control register to configure the operating mode of each port. Proper understanding of the datasheet is essential for configuring and using the device correctly. Pull-up or pull-down resistors may be needed on the I/O lines depending on the application.