MC68882FN25A

Specialized ICS Overview

The MC68882FN25A is a floating-point coprocessor manufactured by NXP USA Inc., designed for the Motorola M68000 processor family. It fully implements the IEEE Standard for Binary Floating-Point Arithmetic (ANSI-IEEE Standard 754-1985). The device features an optimized interface providing over 1.5 times the performance of the MC68881 while maintaining pin and software compatibility. It includes eight 80-bit general-purpose floating-point data registers, a 67-bit arithmetic unit, and a 67-bit barrel shifter. The component supports seven data types and twenty-two on-chip ROM constants, utilizing HCMOS technology for low power consumption.

Specialized ICS Feature Summary

• Fully implements IEEE 754-1985 standard with support for single, double, extended precision, and packed BCD formats.
• Features eight 80-bit floating-point data registers and a 67-bit arithmetic processing unit for high-speed calculations.
• Optimized bus interface delivers more than 1.5x performance compared to the MC68881.
• Includes a 67-bit barrel shifter and special hardware for binary-to-extended format conversion.

Specialized ICS Applications

• Coprocessor extension for MC68020 or MC68030 32-bit microprocessors.
• Peripheral processor for MC68000, MC68008, or MC68010 systems.
• Aerospace On Board Computers and Inertial Reference Systems requiring radiation tolerance verification.

Specialized ICS Procurement Notes

Verify that the MC68882FN25A variant corresponds to the 68-LCC (J-Lead) package as indicated in local product fields. Confirm operational temperature ranges and voltage requirements against the official BR509 datasheet before integration. Ensure system design accounts for the asynchronous nature of the coprocessor interface relative to the main CPU clock.

Specialized ICS Selection Notes

Select this component when upgrading from MC68881 designs to gain performance improvements without changing board layout or software. The device supports virtual memory operations via FSAVE/FRESTORE instructions. Consider the 68-pin PLCC/LCC package constraints for PCB footprint design. Verify compatibility with the specific M68000 family member used in the target architecture.

Specialized ICS Part Context

The MC68882 series serves as a logical extension to the integer processing capabilities of the M68000 family. It allows concurrent operation with the main processor through the M68000 coprocessor interface. The device is implemented using HCMOS technology, combining CMOS and HMOS gates for speed and power efficiency. It functions as a non-DMA coprocessor, relying on the main processor for operand fetching.

Specialized ICS Replacement Considerations

The MC68881 is the predecessor model. While pin and software compatible, the MC68882 offers superior performance. Direct substitution requires verifying that the system can handle the increased throughput and that the unique format word differences do not impact existing context save/restore routines.