NXP Semiconductors MC68EC000EI8

Overview

MC68EC000EI8 from Motorola is a 16-/32-bit embedded controller CPU implementing the M68000 instruction set architecture, featuring a 24-bit address bus (16 MB address space), 16-bit data bus, and no on-chip MMU or FPU. It operates at 8 MHz, uses CMOS technology, and targets cost-sensitive industrial control and legacy embedded systems requiring ROM-based boot and minimal peripheral integration.

For engineers reviewing the MC68EC000EI8 datasheet, MC68EC000EI8 pinout, MC68EC000EI8 application, or MC68EC000EI8 equivalent, key selection criteria include its lack of memory management unit, absence of floating-point unit, 8 MHz maximum clock frequency, 24-bit physical addressing, and compatibility with standard M68000 software toolchains and peripheral support chips like MC68230, MC68231, and MC6850.

Technical Context

The MC68EC000EI8 implements the full M68000 integer instruction set-including all addressing modes (e.g., register indirect with displacement, program counter relative) and supervisor/user privilege levels-but omits the MC68010's virtual memory extensions and MC68020+ enhancements. Its execution unit supports 32-bit internal registers with 16-bit external data path and 24-bit external address path.

It relies on external bus arbitration and timing control, requires separate address latching (e.g., 74LS373), and uses asynchronous memory interface timing with three-state address/data bus control via AS, DTACK, and R/W signals-no internal wait-state generation or cache logic is present.

Key Specifications

Pinout & Package

MC68EC000EI8 is housed in a 68-pin Plastic Leaded Chip Carrier (PLCC) package with J-type leads, designed for socketed or reflow-soldered mounting in space-constrained industrial PCBs. Pinout conforms to Motorola's standard M68EC000 pin assignment, including dedicated AS, DTACK, and R/W control lines for asynchronous bus interfacing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar embedded controller applications.

Compared with MC68000P8, MC68EC000EI8 delivers 93% lower static power and PLCC packaging for modern assembly; compared with MC68EC020RC25, it avoids unnecessary complexity and cost in fixed-function systems where 8 MHz and 16 MB address space remain sufficient.

Availability

MC68EC000EI8 is available at Aetrix Electronics and suitable for industrial PLC controllers, legacy medical device controllers, point-of-sale terminals, and avionics maintenance interfaces requiring stable component supply across extended product lifecycles.

Supply support for MC68EC000EI8 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

Motorola Semiconductor (now NXP Semiconductors) pioneered the M68000 family and defined the de facto standard for 16-/32-bit embedded computing in the 1980s and 1990s.

The MC68EC000EI8 belongs to Motorola's Embedded Controller subfamily, designed specifically for cost-optimized, ROM-based systems where MMU/FPU overhead is unnecessary-targeting industrial automation, instrumentation, and legacy infrastructure equipment.

FAQ

Does the MC68EC000EI8 include an on-chip memory management unit (MMU)?

No, the MC68EC000EI8 does not integrate an MMU. It provides a flat 24-bit address space (16 MB) with no virtual memory support. Systems requiring memory protection or paging must implement external logic or use a different processor such as the MC68EC030. This design choice reduces cost and power while maintaining full M68000 software compatibility for simpler embedded applications.

What is the maximum operating frequency of the MC68EC000EI8?

The MC68EC000EI8 is rated for a maximum clock frequency of 8 MHz. This speed is guaranteed across the commercial temperature range (0°C to +70°C) with proper decoupling and 5 V ±5% supply. Exceeding this frequency may result in undefined instruction execution or bus timing violations due to internal propagation delays in the CMOS implementation.

Is the MC68EC000EI8 pin-compatible with the original MC68000?

Yes, the MC68EC000EI8 is pin-compatible with the MC68000 in the same PLCC-68 package variant. Signal names, pin positions, and electrical timing (e.g., AS setup/hold, DTACK assertion window) match the MC68000P8 specification. However, the MC68EC000EI8 uses CMOS technology and draws significantly less current, allowing direct substitution in most existing MC68000-based designs without layout changes.

Does the MC68EC000EI8 support floating-point operations natively?

No, the MC68EC000EI8 lacks an integrated floating-point unit (FPU). Floating-point calculations must be performed in software or offloaded to an external coprocessor such as the MC68881 or MC68882. The instruction set includes F-line opcodes to enable coprocessor handshake, but no hardware execution resources are present on-die for FP arithmetic.

What package type is used for the MC68EC000EI8?

The MC68EC000EI8 is supplied in a 68-pin Plastic Leaded Chip Carrier (PLCC) package with J-shaped leads. This surface-mount package offers mechanical robustness, thermal performance suitable for industrial environments, and compatibility with zero-insertion-force (ZIF) sockets for prototyping and field serviceability.