Renesas CS82C55AZ96S2705

Overview

CS82C55AZ96S2705 from Intersil is a CMOS Programmable Peripheral Interface (PPI) IC designed for parallel I/O expansion in 8-bit microprocessor systems. It provides 24 programmable I/O pins across three 8-bit ports (A, B, C), supports three operational modes (Mode 0/1/2), delivers 2.5mA drive capability per pin, and operates at up to 8MHz with 80C86/80C88 CPUs in industrial temperature range (–40°C to +85°C). It is used in legacy industrial controllers for keyboard scanning, LED display driving, and printer interface logic.

For engineers reviewing the CS82C55AZ96S2705 datasheet, CS82C55AZ96S2705 pinout, CS82C55AZ96S2705 application, or CS82C55AZ96S2705 equivalent, key selection criteria include its 44-lead PLCC package, TTL-compatible 5V operation, bus-hold circuitry eliminating external pull-ups, direct bit set/reset on Port C, and mode-selectable strobed/bidirectional I/O behavior - all critical for retrofitting or maintaining 8086-era embedded control hardware.

Technical Context

The CS82C55AZ96S2705 implements a static CMOS architecture with bus-hold inputs on all ports, enabling stable logic levels without external resistors across the full –40°C to +85°C range. Its control logic decodes A0/A1 address lines with RD/WR/CS to select Port A/B/C or the control register, supporting both read and write operations via an 8-bit bidirectional data bus (D0–D7).

Port configuration is fully software-defined via an 8-bit control word that sets Mode 0 (basic I/O), Mode 1 (strobed I/O with handshaking using Port C signals), or Mode 2 (bidirectional bus on Port A with dedicated control bits on Port C). Interrupt enable/disable for Ports A and B is managed independently via bit set/reset operations on PC4, PC2, PC6, and PC2 respectively.

Key Specifications

Pinout & Package

CS82C55AZ96S2705 is housed in a 44-lead Plastic Leaded Chip Carrier (PLCC) package with J-lead geometry (PKG DWG N44.65), RoHS-compliant matte tin finish, and tape-and-reel delivery (suffix "96").

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable peripheral interface applications.

Compared with CS82C55AZ96S2705, CS82C55A-5Z lacks industrial temperature support but offers lower unit cost, while IS82C55AZ matches all specifications and qualifies as a seamless second-source option with no design or qualification impact.

Availability

CS82C55AZ96S2705 is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy printer interface controllers, keyboard scanners, and LED segment display drivers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CS82C55AZ96S2705 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Intersil Corporation was a U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs, later acquired by Renesas Electronics in 2017. Known for robust industrial-grade timing, interface, and power management solutions.

The CS82C55AZ96S2705 belongs to Intersil's legacy CMOS PPI product line, engineered specifically for backward-compatible integration into 8086/8088-based industrial control systems requiring reliable, low-power, pin-compatible replacements for NMOS 8255A devices.

FAQ

What is the maximum operating frequency supported by the CS82C55AZ96S2705?

The CS82C55AZ96S2705 supports up to 8MHz operation, enabling zero-wait-state interfacing with 80C86 and 80C88 microprocessors. This frequency rating is validated across the full –40°C to +85°C industrial temperature range and assumes proper 0.1µF VCC–GND decoupling. Performance at 8MHz is maintained without external clock conditioning or timing margining.

Does the CS82C55AZ96S2705 require external pull-up or pull-down resistors on its I/O pins?

No, the CS82C55AZ96S2705 does not require external pull-up or pull-down resistors due to integrated bus-hold circuitry on all I/O pins (PA0–PA7, PB0–PB7, PC0–PC7). This feature actively maintains valid logic states during tri-state conditions or floating inputs, ensuring noise immunity and stable operation in all three operating modes without added passive components.

How is interrupt enable/disable controlled for Port A and Port B in the CS82C55AZ96S2705?

Interrupt enable/disable for Port A and Port B in the CS82C55AZ96S2705 is controlled exclusively via the bit set/reset function on Port C. INTE A is toggled by setting or resetting PC4 (for input mode) or PC6 (for output mode); INTE B is controlled by PC2 in both input and output configurations. These operations use dedicated control words written to Port C and do not require reprogramming the entire mode configuration.

Can the CS82C55AZ96S2705 be used as a bidirectional data bus interface?

Yes, the CS82C55AZ96S2705 supports bidirectional bus operation in Mode 2, which is available only on Port A. In this mode, Port A functions as an 8-bit bidirectional data bus while Port C provides five dedicated control lines (STB, IBF, OBF, ACK, INTR) and two interrupt enable bits. This configuration enables shared-memory or peripheral bus arbitration in legacy 8086 systems without external transceivers.

Is the CS82C55AZ96S2705 pin-compatible with the original NMOS 8255A?

Yes, the CS82C55AZ96S2705 is fully pin-compatible with the NMOS 8255A, sharing identical pin assignments, signal definitions, and PLCC-44 footprint. It retains the same control word format, mode definitions, and register addressing scheme, allowing direct substitution in existing 8255A-based designs without PCB or firmware modifications - provided voltage and timing constraints are met.