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MC68060 PRODUCT INFORMATION
MOTOROLA
Leveraging many of the same performance enhancements used by RISC designs as well as providing
innovative architectural techniques, the MC68060 harnesses new levels of performance for the M68000 family.
Incorporating 2.5 million transistors on a single piece of silicon, the MC68060 employs a deep pipeline, dual
issue superscalar execution, a branch cache, a high-performance floating-point unit (MC68060 only), eight
Kbytes each of on-chip instruction and data caches, and dual on-chip demand paging MMUs (MC68060 and
MC68LC060 only). The MC68060 allows simultaneous execution of two integer instructions (or an integer and
a floating-point instruction) and one branch instruction during each clock.
The MC68060 features a full internal Harvard architecture. The instruction and data caches are designed to
support concurrent instruction fetch, operand read, and operand write references on every clock. Separate 8-
Kbyte instruction and 8-Kbyte data caches can be frozen to prevent allocation over time-critical code or data.
The independent nature of the caches allows instruction stream fetches, data-stream fetches, and external
accesses to occur simultaneously with instruction execution. The operand data cache is four-way banked to
permit simultaneous read and write access each clock.
A very high bandwidth internal memory system coupled with the compact nature of the M68000 family code
allows the MC68060 to achieve extremely high levels of performance, even when operating from low-cost
memory such as a 32-bit wide dynamic random access memory system.
Instructions are fetched from the internal cache or external memory by a four-stage instruction fetch pipeline.
The MC68060 variable-length instruction system is internally decoded into a fixed-length representation and
channeled into an instruction buffer. The instruction buffer acts as a FIFO which provides a decoupling
mechanism between the instruction fetch unit and the operand execution units. Fixed format instructions are
dispatched to dual four-stage pipelined RISC operand execution engines where they are then executed.
The branch cache also plays a major role in achieving the high performance levels of the MC68060. It has
been implemented such that most branches are executed in zero cycles. Using a technique known as branch
folding, the branch cache allows the instruction fetch pipeline to detect and change the instruction prefetch
stream before the change of flow affects the instruction execution engines, minimizing the need for pipeline
refill.
In addition to substantial cost and performance benefits, the MC68060 also offers advantages in power
consumption and power management. The MC68060 automatically minimizes power dissipation by using a
fully-static design, dynamic power management, and low-voltage operation. It automatically powers-down
internal functional blocks that are not needed on a clock-by-clock basis. Explicitly, the MC68060 power
consumption can be controlled from the operating system. Although the MC68060 operates at a lower
operating voltage, it directly interfaces to both 3-V and 5-V peripherals and logic.
Complete code compatibility with the M68000 family allows the designer to draw on existing code and past
experience to bring products to market quickly. There is also a broad base of established development tools,
including real-time kernels, operating systems, languages, and applications, to assist in product design. The
functionality provided by the MC68060 makes it the ideal choice for a range of high-performance embedded
applications and computing applications. With M68000 family code compatibility, the MC68060 provides a
range of upgrade opportunities to virtually any existing MC68040 application.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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