NXP Semiconductors MC68EC000EI16

Overview

MC68EC000EI16 from Motorola is a 16-/32-bit embedded controller CPU implementing the M68000 instruction set architecture, featuring a 16-bit external data bus, 24-bit address bus supporting up to 16 MB of physical memory, and no on-chip MMU or FPU. It operates at 16 MHz and targets cost-sensitive industrial control, point-of-sale terminals, and legacy instrumentation systems requiring ROM-based boot and deterministic interrupt response.

For engineers reviewing the MC68EC000EI16 datasheet, MC68EC000EI16 pinout, MC68EC000EI16 application, or MC68EC000EI16 equivalent, key selection criteria include its 16-bit bus interface, lack of memory management unit, compatibility with M68000-family software tools and assemblers, and suitability for systems where external peripherals handle memory mapping and floating-point operations.

Technical Context

The MC68EC000EI16 implements the full M68000 integer instruction set-including all addressing modes (e.g., register indirect with displacement, PC-relative, absolute long)-and supports supervisor/user privilege levels via status register control. Its execution unit uses a three-stage pipeline (fetch/decode/execute) and handles 8-, 16-, and 32-bit data operations with consistent endianness (big-endian).

It relies entirely on external logic for bus arbitration, wait-state generation, and memory-mapped I/O decoding. Exception handling follows the M68000 family vector table layout (256-byte base, 4-byte vectors), supporting 72 defined exception types including reset, bus error, address error, and trace exceptions-critical for real-time debugging in embedded environments.

Key Specifications

Pinout & Package

MC68EC000EI16 is housed in an 84-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead configuration, designed for socketed or reflow-soldered mounting. Thermal resistance (θ_JA) is 45°C/W, and maximum junction temperature is 110°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68EC000EI16, MC68000RC16 adds MMU and 32-bit bus overhead without runtime benefit in flat-memory systems, while MC68EC020RC50 delivers higher performance and scalability at the cost of software porting effort and increased BOM complexity.

Availability

MC68EC000EI16 is available at Aetrix Electronics and suitable for industrial PLC controllers, point-of-sale terminals, medical instrument displays, and legacy test equipment requiring stable component supply and long-term obsolescence management.

Supply support for MC68EC000EI16 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 architecture and delivered industry-standard microprocessors for embedded, industrial, and computing applications from the 1980s onward.

The MC68EC000EI16 belongs to the Embedded Controller subfamily-designed specifically for cost-sensitive, ROM-based systems where MMU/FPU were unnecessary, emphasizing software compatibility, thermal efficiency, and pinout stability over raw performance.

FAQ

What is the maximum operating frequency of the MC68EC000EI16?

The MC68EC000EI16 is rated for a maximum clock frequency of 16 MHz under specified voltage (5 V ±5%) and temperature (0°C to +70°C) conditions. This frequency defines its instruction throughput ceiling and constrains timing margins for external memory and peripheral access-designers must ensure DTACK assertion meets setup/hold requirements at this rate.

Does the MC68EC000EI16 include an on-chip memory management unit (MMU)?

No, the MC68EC000EI16 does not contain an on-chip MMU. It relies on external logic or flat memory mapping for address translation. This distinguishes it from the MC68000 and enables lower cost and power consumption, but precludes use with virtual-memory operating systems unless supplemented by discrete MMU chips like the MC68851.

Can the MC68EC000EI16 execute code written for the original MC68000?

Yes, the MC68EC000EI16 implements the complete M68000 integer instruction set and addressing modes, making it binary-compatible with MC68000 software. No source modifications are needed, though developers should verify timing assumptions (e.g., bus cycle duration) due to differences in external bus interface behavior.

What package type is used for the MC68EC000EI16?

The MC68EC000EI16 is packaged in an 84-pin Plastic Leaded Chip Carrier (PLCC) with J-leads. This surface-mount package supports socketed prototyping and reflow assembly, offers good thermal dissipation (θ_JA = 45°C/W), and maintains pin compatibility with other M68000-family PLCC variants for board reuse.

Is there an on-chip floating-point unit (FPU) in the MC68EC000EI16?

No, the MC68EC000EI16 does not integrate an FPU. Floating-point arithmetic must be performed in software or delegated to an external coprocessor such as the MC68881 or MC68882, which connect via the M68000-family coprocessor interface and share the same bus and exception model as the MC68EC000EI16.