NXP Semiconductors MC68HC000EI16

Overview

MC68HC000EI16 from Freescale Semiconductor (formerly Motorola) is a CMOS 16-bit microprocessor compatible with the M68000 architecture, featuring 24-bit address bus, 16-bit data bus, and 16 MHz maximum clock frequency. It executes the full M68000 instruction set in user and supervisor modes, supports asynchronous and synchronous bus timing, and targets embedded control systems requiring deterministic real-time response.

For engineers reviewing the MC68HC000EI16 datasheet, MC68HC000EI16 pinout, MC68HC000EI16 application, or MC68HC000EI16 equivalent, key selection considerations include its 16 MHz operation at 5 V, 64-pin DIP package, bus arbitration support, exception vector handling, and compatibility with legacy M68000 peripheral interfaces.

Technical Context

The MC68HC000EI16 implements the M68000 instruction set architecture with a three-stage pipeline (fetch, decode, execute), 16 general-purpose 32-bit registers (eight data, eight address), and a 16-bit external data path. It uses a 24-bit physical address space supporting up to 16 MB memory, with separate user/supervisor privilege modes enforced via status register bits.

Bus interface logic includes asynchronous DTACK, BERR, and HALT signals, programmable interrupt levels (seven vectorable interrupts plus reset), and 3-wire bus arbitration (BR, BG, BGACK). Clock input accepts TTL/CMOS-compatible square wave; internal timing derives from divided clock for instruction cycle synchronization.

Key Specifications

Pinout & Package

MC68HC000EI16 is housed in a 64-pin Dual In-Line Package (DIP), case 740-03 (L suffix), with 0.6-inch body width and 0.1-inch pin pitch. Pin functions are electrically and functionally identical to MC68000 but implemented in lower-power CMOS technology.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit microprocessor applications.

Compared with MC68HC000EI16, the MC68000P16 offers identical functionality but higher thermal load, while the MC68EC000RC20 sacrifices bus compatibility for smaller footprint and higher clock speed-making MC68HC000EI16 the optimal choice for legacy M68000 system upgrades requiring low-power CMOS operation.

Availability

MC68HC000EI16 is available at Aetrix Electronics and suitable for industrial PLC controllers, legacy test equipment, medical diagnostic interfaces, and retro computing platforms requiring stable component supply and long-term obsolescence management.

Supply support for MC68HC000EI16 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

Freescale Semiconductor (now part of NXP Semiconductors) was a leading designer of embedded processors, known for the M68K family and automotive microcontrollers.

The MC68HC000 belongs to the M68000 family, designed for general-purpose 16/32-bit computing in industrial control, instrumentation, and early workstations where binary compatibility and deterministic timing were critical.

FAQ

What is the maximum operating frequency of the MC68HC000EI16?

The MC68HC000EI16 is rated for a maximum clock frequency of 16 MHz under specified 5 V ±5% supply and –40°C to +85°C operating conditions. This frequency defines the upper limit for instruction execution rate and synchronous bus timing; exceeding it may cause timing violations or undefined behavior. The MC68HC000EI16 achieves this speed using CMOS technology, which provides better noise immunity and lower power than earlier NMOS versions like the MC68000P16.

Does the MC68HC000EI16 support the full M68000 instruction set?

Yes, the MC68HC000EI16 implements the complete M68000 instruction set architecture, including all addressing modes, privilege-level instructions (e.g., MOVE from SR), and exception handling mechanisms. Software compiled for the original MC68000 runs unchanged on the MC68HC000EI16, making it a drop-in upgrade for power-sensitive applications. The MC68HC000EI16 retains identical programmer's models for both user and supervisor modes as defined in the M68000 User's Manual.

What package type is used for the MC68HC000EI16?

The MC68HC000EI16 is packaged in a 64-pin Dual In-Line Package (DIP) with case number 740-03 (L suffix), measuring 0.6 inches wide and featuring 0.1-inch pin spacing. This package matches the pinout of the MC68000P16, enabling direct socket replacement in existing through-hole designs. The MC68HC000EI16 does not use QFP, PGA, or PLCC variants-only the 64-pin DIP configuration is offered for this specific speed grade and temperature range.

How does the MC68HC000EI16 handle bus arbitration?

The MC68HC000EI16 implements 3-wire bus arbitration using BR (Bus Request), BG (Bus Grant), and BGACK (Bus Grant Acknowledge) signals. When asserting BR, the MC68HC000EI16 waits for BG before driving the address/data bus; BGACK confirms receipt of the grant. This protocol allows multiple masters-including DMA controllers-to share the same bus without contention. The MC68HC000EI16 does not support 2-wire arbitration or cache coherency protocols.

Is the MC68HC000EI16 compatible with M6800 peripheral interfaces?

Yes, the MC68HC000EI16 maintains full electrical and timing compatibility with M6800-series peripherals as documented in Section 10.11 of the M68000 User's Manual. Its AS, DS, R/W, and VMA signals align with M6800 timing requirements, enabling direct connection to legacy 8-bit peripherals such as the MC6821 PIA or MC6850 ACIA without translation logic. This compatibility is preserved across all MC68HC000 speed grades, including the MC68HC000EI16.