NXP Semiconductors MC68LC060RC50

Overview

MC68LC060RC50 from Motorola is a 32-bit superscalar microprocessor without integrated floating-point unit (FPU) or memory management unit (MMU), operating at 50 MHz with on-chip 8 KB instruction cache and 8 KB data cache, supporting 32-bit address/data bus, used in embedded control and real-time industrial systems requiring deterministic execution and legacy 68k software compatibility.

For engineers reviewing the MC68LC060RC50 datasheet, MC68LC060RC50 pinout, MC68LC060RC50 application, or MC68LC060RC50 equivalent, key selection considerations include FPU/MMU omission, 50 MHz clock rating, cache coherency behavior, bus timing compliance with synchronous/asynchronous memory interfaces, and thermal management for plastic QFP packaging.

Technical Context

The MC68LC060RC50 implements a dual-pipeline integer unit with instruction fetch, decode, and operand execution stages, enabling concurrent execution of two integer instructions per cycle under optimal conditions. It supports full 32-bit address space (4 GB) via external address translation when MMU is disabled, and uses separate 8 KB unified-tag, split-data caches with writethrough and copyback modes.

Bus operation complies with synchronous and asynchronous protocols using TS/TIP/TA handshake signals, with programmable transfer size (byte/word/long-word), burst capability, and snoop support for cache coherency in multiprocessor configurations. The processor includes JTAG (IEEE 1149.1) test access port and debug pipe control for boundary-scan and real-time trace.

Key Specifications

Pinout & Package

MC68LC060RC50 is housed in a 160-pin Plastic Quad Flat Pack (PQFP) package with 0.65 mm lead pitch, designed for surface-mount assembly and thermal dissipation in industrial temperature range (–40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68EC060RC50, MC68LC060RC50 provides address translation caches for efficient software-based virtual memory, while compared with MC68060RC50, it eliminates FPU/MMU silicon area and power draw-making it optimal for deterministic real-time control where floating-point and memory protection are extraneous.

Availability

MC68LC060RC50 is available at Aetrix Electronics and suitable for industrial motion control, legacy avionics upgrades, and telecom line card designs requiring stable component supply across extended product lifecycles.

Supply support for MC68LC060RC50 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 part of NXP Semiconductors) was a pioneer in 68k architecture, delivering high-reliability microprocessors for aerospace, industrial, and telecom markets from the 1970s through early 2000s.

The MC68LC060RC50 belongs to Motorola's M68060 family, designed specifically for embedded applications demanding binary compatibility with legacy 68k software while delivering higher performance than earlier MC68020/MC68030 derivatives.

FAQ

Does the MC68LC060RC50 include an integrated floating-point unit (FPU)?

No, the MC68LC060RC50 does not contain an integrated floating-point unit. It is explicitly defined as the "LC" variant-Low Cost, no FPU, no MMU-distinguishing it from the full-featured MC68060RC50. Floating-point operations must be performed in software or offloaded to an external coprocessor. This omission reduces power consumption and die area, making the MC68LC060RC50 appropriate for deterministic real-time control where floating-point math is unnecessary or handled externally.

What is the maximum operating frequency of the MC68LC060RC50?

MC68LC060RC50 is rated for a maximum clock frequency of 50 MHz, as specified in Motorola's M68060 User's Manual and electrical characteristics documentation. This rating assumes proper decoupling, thermal management within the industrial temperature range (–40°C to +85°C), and adherence to timing specifications for address setup/hold, data valid windows, and bus handshake signals. Exceeding 50 MHz may result in undefined behavior or timing violations.

How does cache coherency work on the MC68LC060RC50?

The MC68LC060RC50 implements hardware cache coherency via the dedicated SNOOP input pin. When an external agent (e.g., DMA controller or second CPU) writes to memory that resides in the MC68LC060RC50's data cache, assertion of SNOOP triggers automatic invalidation of the affected cache line. This mechanism avoids software cache-flush overhead in multiprocessor or shared-memory systems, ensuring data consistency without requiring explicit cache management instructions in application code.

Is the MC68LC060RC50 pin-compatible with other M68060 family members?

Yes, the MC68LC060RC50 shares identical pinout and package (160-pin PQFP) with the MC68060RC50 and MC68EC060RC50, enabling direct PCB-level substitution in many designs. However, functional differences-including absence of FPU/MMU, different reset behavior, and variations in cache control register bit definitions-require firmware and hardware configuration updates. Pin compatibility does not imply drop-in software or electrical equivalence without validation.

What debug and test capabilities does the MC68LC060RC50 provide?

The MC68LC060RC50 integrates full IEEE 1149.1 (JTAG) boundary-scan support via dedicated TCK, TMS, TDI, TDO, and TRST pins. It also supports debug pipe mode for real-time instruction trace without CPU halting. These features enable in-circuit testing, firmware validation, and non-intrusive runtime analysis-critical for safety-certified applications such as avionics and medical devices where the MC68LC060RC50 is commonly deployed.