Emerson / Motorola MVME133XT VMEbus Module

The Emerson/Motorola MVME133XT is a double-high, single-wide VMEbus module built around a 25 MHz MC68020 microprocessor paired with a 25 MHz MC68882 Floating Point Coprocessor. Designed for industrial and embedded systems requiring deterministic real-time processing, this module delivers 4MB of shared local Dynamic RAM accessible via VMEbus, battery-backed persistent storage (2KB SRAM and real-time clock), and full VMEbus master/slave/system controller capabilities across A32/D32, A32/D16, A24/D32, and A24/D16 address/data configurations.

Technical Specifications

Processor: Motorola MC68020 at 25 MHz

Coprocessor: Motorola MC68882 FPC at 25 MHz

RAM: 4MB shared local DRAM (VMEbus accessible)

ROM: 256KB maximum (four 28-pin JEDEC sockets, two 16-bit banks)

Battery-backed Storage: 2KB SRAM and Real-Time Clock

VMEbus Addressing: A32/D32 native; A32/D16, A24/D32, A24/D16 compatible

VMEbus Functions: Master, Slave, System Controller, Interrupter, Interrupt Handler (all seven levels)

Serial Ports: One EIA-232-D debug port (DB25); two multiprotocol ports (one EIA-232-D, one EIA-485)

Timers: Three 8-bit programmable timers (tick and watchdog)

Power: +12 Vdc @ 100 mA typical, 250 mA max; −12 Vdc @ 100 mA typical, 250 mA max

Operating Temperature: 0°C to 55°C with forced air cooling (71 CFM axial fan)

Compliance: FCC Class A; EN60950

Key Features

Battery-backed real-time clock and SRAM for uninterrupted timekeeping across power cycles

Multifunction Peripheral with integrated debug capabilities and three independent timers

Four front-panel status LEDs (RUN, HALT, FAIL, SCON) and user controls (ABORT, RESET)

Full VMEbus requester functionality with jumper-selectable interrupt level

Flexible memory configuration supporting up to 256KB ROM/PROM/EPROM/EEPROM

Typical Applications Process control, data acquisition, real-time monitoring, embedded system controllers, and VMEbus-based distributed processing nodes requiring floating-point computation and persistent state management.

Compatibility & Integration Issued as a plug-in VMEbus module compatible with standard 6U VMEbus backplanes. Serial connectivity via EIA-232-D and EIA-485 interfaces supports legacy industrial protocols. Interrupter and interrupt handler support enables seamless integration into multi-master VMEbus environments.