NXP Semiconductors MC68HC000CRC12

Overview

MC68HC000CRC12 from Freescale Semiconductor (formerly Motorola) is a CMOS 16/32-bit microprocessor with 32-bit internal architecture, 16-bit data bus, and 24-bit address bus supporting up to 16 MB memory space. It operates at 12 MHz maximum clock frequency, features two privilege modes (User/Supervisor), and implements full M68000 instruction set compatibility. It was widely used in industrial controllers and embedded instrumentation requiring deterministic real-time execution.

For engineers reviewing the MC68HC000CRC12 datasheet, MC68HC000CRC12 pinout, MC68HC000CRC12 application, or MC68HC000CRC12 equivalent, key selection criteria include bus timing compliance (asynchronous/synchronous modes), exception vector handling, DTACK/BERR handshake behavior, and thermal/power constraints for legacy board-level integration.

Technical Context

The MC68HC000CRC12 implements the classic M68000 architecture with a 32-bit internal ALU and register file, but external interface limited to 16-bit data transfers and 24-bit addressing. Its asynchronous bus protocol relies on DTACK for cycle termination and supports three-wire bus arbitration via BR, BG, and BGACK signals.

It executes instructions using a five-stage pipeline (fetch, decode, operand fetch, execute, writeback) and handles exceptions-including reset, interrupts, bus errors, and address errors-via dedicated 16-byte-aligned vector table entries. The status register includes interrupt mask bits (I0–I2), supervisor/user mode flag, and condition codes (N, Z, V, C).

Key Specifications

Pinout & Package

MC68HC000CRC12 is housed in a 68-pin Ceramic Quad Flat Pack (Case 765A-05, RC suffix), measuring 27.94 mm × 27.94 mm with 0.65 mm lead pitch and gull-wing leads. The package is hermetically sealed for high-reliability industrial use.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16/32-bit microprocessor applications.

Compared with MC68HC000CRC12, the MC68EC000RC16 offers higher clock speed but removes critical bus control signals needed for general-purpose expansion, while the MC68000P12 provides identical functionality in HMOS with significantly higher power draw and less robust packaging-making MC68HC000CRC12 the optimal choice for thermally constrained, field-deployable industrial systems requiring full bus flexibility.

Availability

MC68HC000CRC12 is available at Aetrix Electronics and suitable for industrial PLC controllers, legacy test equipment, medical diagnostic interfaces, avionics data recorders, and embedded instrumentation requiring stable component supply and long-term obsolescence management.

Supply support for MC68HC000CRC12 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, analog, and connectivity solutions, founded as Motorola's semiconductor division.

The MC68HC000 belongs to the M68000 family-a foundational 16/32-bit microprocessor line designed for real-time control, instrumentation, and industrial computing where deterministic timing and software compatibility were critical.

FAQ

What is the maximum operating frequency of the MC68HC000CRC12?

The MC68HC000CRC12 is rated for a maximum clock frequency of 12 MHz. This specification is validated under commercial temperature conditions (0 °C to +70 °C) and +5 V ±5% supply. Exceeding this frequency may result in timing violations, especially in asynchronous bus cycles dependent on DTACK assertion timing. The MC68HC000CRC12 achieves this speed using CMOS technology, enabling lower power versus HMOS predecessors like the MC68000P12.

Does the MC68HC000CRC12 support 32-bit data operations?

Yes, the MC68HC000CRC12 features a full 32-bit internal architecture-including 32-bit registers, ALU, and instruction set-but its external data bus is limited to 16 bits. As a result, 32-bit memory accesses require two consecutive bus cycles. The MC68HC000CRC12 maintains complete binary compatibility with the original MC68000, allowing reuse of existing M68K assembly and C code without modification.

What package type is used for the MC68HC000CRC12?

The MC68HC000CRC12 uses a 68-pin Ceramic Quad Flat Pack (CQFP), designated Case 765A-05 with RC suffix. This hermetic ceramic package provides superior thermal stability and moisture resistance compared to plastic variants, making it suitable for industrial and aerospace applications where long-term reliability under thermal cycling is required.

How does the MC68HC000CRC12 handle bus errors?

The MC68HC000CRC12 asserts the BERR pin low upon detecting an invalid memory or I/O access, then automatically vectors to exception #2 (bus error vector). The processor pushes program counter and status register onto the supervisor stack and begins executing the bus error handler. Unlike the MC68010, the MC68HC000CRC12 does not implement delayed bus error reporting-it responds immediately upon address/data phase failure.

Is the MC68HC000CRC12 pin-compatible with other M68000 family members?

The MC68HC000CRC12 shares identical pinout and signal definitions with the MC68000P12 and MC68000L12 in the 68-pin DIP and CQFP packages, respectively. However, it is not pin-compatible with MC68008 (48-pin), MC68010 (64-pin), or MC68EC000 (64-pin with different signal assignment). Always verify package drawing 11-11 (Case 765A-05) and signal mapping in Section 3 of the M68000 User's Manual before substitution.