MOTOROLA M68040 USER’S MANUAL B- 1
All references to MC68EC040 also apply to the MC68EC040V.
Refer to Appendix C MC68040V and MC68EC040V for more
information on the MC68EC040V.
The MC68EC040 is Motorola's third generation of M68000-compatible, high-performance,
32-bit microprocessors. The MC68EC040 is an embedded controller employing a highly
integrated architecture to provide very high performance in a monolithic HCMOS device.
The MC68EC040 integrates an MC68040-compatible integer unit, an access control unit
(ACU), and independent 4-Kbyte instruction and data caches. A six-stage instruction
pipeline, multiple internal buses, and a full internal Harvard architecture, including
separate caches for both instruction and data accesses, provides a high degree of
instruction execution parallelism. The inclusion of on-chip bus snooping logic, which
directly supports cache coherency in multimaster applications, enhances cache
The MC68EC040 is user-object-code compatible with previous members of the M68000
family and is specifically optimized to reduce the execution time of compiler-generated
code. The MC68EC040 is pin compatible with the MC68040 and MC68LC040. The
MC68EC040 is implemented in Motorola’s latest HCMOS technology, providing an ideal
balance between speed, power, and physical device size. Figure B-1 provides a simplified
block diagram of the MC68EC040.
The main features of the MC68EC040 include:
• MC68040-Compatible Integer Execution Unit
• 4-Kbyte Instruction Cache and 4-Kbyte Data Cache Accessible Simultaneously
• 32-Bit, Nonmultiplexed External Address and Data Buses with Synchronous Bursting
• User-Object-Code Compatible with All M68000 Microprocessors
• Concurrent Integer Unit, ACU, and Bus Controller Operation Maximizes Throughput
• Low-Latency Bus Accesses for Reduced Cache-Miss Penalty
• Multimaster/Multiprocessor Support via Bus Snooping
• 4-Gbyte Direct Addressing Range