MC68EC000EI8
MC68EC000EI8 - 8MHz EC000 32-Bit MPU 68-PLCC | NXP
The NXP MC68EC000EI8 is an 8 MHz, 32-bit reduced-cost version of the MC68000 microprocessor in a 68-pin PLCC (J-Lead) package, designed for embedded systems that need M68000 instruction set compatibility without the full 68000 peripheral set. It features a 32-bit programming model with eight data registers and eight address registers, a 16-bit external data bus, and a 24-bit external address bus, supporting up to 16 MB of linear address space. The part runs from a 3.3 V or 5 V supply and integrates an 8 MHz maximum internal bus frequency, which is fully static for low-power standby operation.
A microprocessor (MPU) is a single-chip CPU that fetches, decodes, and executes instructions from external memory, while peripherals such as timers, UARTs, and bus controllers are implemented off-chip. The MC68EC000 belongs to the M68000 family of CISC processors, sitting in the hierarchy of microprocessor -> 32-bit MPU -> CISC processor -> M68k family -> embedded computing core. Compared with a microcontroller (MCU), an MPU relies on external ROM/RAM and discrete peripherals, which gives designers greater flexibility in memory sizing and I/O expansion for industrial control and legacy computing platforms.
Key features include full MC68000 user instruction set compatibility, 8 data and 8 address 32-bit registers, 24-bit address bus (16 MB), 16-bit data bus, seven user-visible addressing modes, six level hardware interrupt structure (autovectored), and static operation allowing DC to 8 MHz clock input. The 68-PLCC package provides robust mechanical mounting for through-hole-style sockets used in legacy VME boards, industrial controllers, and aerospace instrumentation.
The architecture is a true big-endian CISC core that prefetches instructions into a 3-word FIFO, providing roughly 2x throughput versus pure sequential execution at the same clock. The EC000 omits the MC68000's M6800 peripheral emulation and bus arbitration signals, simplifying the bus interface and shortening design cycles. Sustained throughput reaches ~1 MIPS at 8 MHz on typical instruction mixes, suitable for low-to-mid complexity control and HMI applications.
Typical applications include industrial PLC controllers, legacy VMEbus single-board computers, embedded operator interfaces, point-of-sale terminals, avionics retrofit systems, and educational computer platforms. The M68k software ecosystem (OS-9, RTOS, and legacy UNIX-like toolchains) makes the EC000 a drop-in host for established firmware libraries.
When designing with the MC68EC000, ensure bus termination on the address/data lines and observe the asynchronous bus timing margins in the manufacturer datasheet. Use a phase-locked clock driver to maintain DTFC skew under the 50 ns hold time requirement, and place decoupling capacitors within 25 mm of each supply pin to suppress switching noise on the 16-bit data bus.
This page synthesizes distributor pricing, drop-in pin-compatible equivalents in the same 68-PLCC footprint, and practical design notes not found in the manufacturer datasheet alone.
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