RadiSys EXP-MX250 Hard Drive and Floppy Drive Controller Module

The RadiSys EXP-MX250 is a 6U VMEbus mass storage controller module that provides IDE hard drive and floppy drive interface capabilities for RadiSys embedded PC systems. The module occupies two to three VMEbus slots and mounts as the right-most device in an EXM expansion subplane. It delivers dual-interface connectivity: internal IDE hard drives, external SCSI hard drives up to 2 GB (MS-DOS environment), and standard 3.5″ or 5.25″ floppy drives via dedicated front-panel connectors.

– Technical Specifications

• Interface Standard: IDE (Integrated Device Electronics) for internal hard drive connectivity
• VMEbus Slot Occupancy: Two to three slots, dependent on internal hard disk capacity and physical size
• Form Factor: 6U VMEbus module; main board shortened to prevent mechanical interference with subplane-mounted controllers
• Power Supply Requirements: +5V and +12V from VMEbus (+12V mandatory for hard disk operation)
• External SCSI Port: 50-pin connector, ANSI single-ended non-shielded standard, supports external SCSI hard drives to 2 GB under MS-DOS only
• External Floppy Connector: 34-pin connector for 3.5″ or 5.25″ floppy drives; incompatible with drives drawing 5V from ribbon cable
• Status Indicators: Three LEDs—VMEbus +5V presence, +12V presence, and hard disk activity

– Key Features

• Multi-interface mass storage support within single module footprint
• Compatible with all PC operating systems and MS-DOS environments
• Front-panel SCSI port for secondary storage expansion (2 GB maximum, MS-DOS)
• Dual power-supply monitoring with LED status display
• Mechanical design prevents slot interference in systems with subplane controllers

– Typical Applications

• Internal and external mass storage for VMEbus-based embedded computers
• Dual hard drive configurations using SCSI secondary interface
• Legacy floppy drive support in PC-based industrial systems

– Compatibility & Integration

The EXP-MX250 requires installation within an EXM expansion subplane (BP-3, BP-4, BP-5, or BP-6 compatible). It cannot coexist with EXM-3 or EXM-9 disk controllers, or with EXM-MX series disk drives. Most standard 3.5″ and 5.25″ floppy drives are supported; verification of ribbon cable power specifications is required.