RadiSys EXM-2A Flash Disk Module

The RadiSys EXM-2A Flash Disk Module is a semiconductor-based storage device engineered for rugged embedded applications. It combines flash and SRAM memory technologies in a compact form factor, interfacing with embedded PCs through the EXM expansion interface—electrically compatible with the PC ISA bus. This allows the module to function with standard PC software while delivering the performance and durability required by mission-critical systems. The flash memory portion operates as a read-only hard disk suitable for boot operations, while the SRAM portion provides read/write access as a non-bootable disk.

– Technical Specifications

• Memory Configuration: Flash and SRAM. Capacity determined by part number designation (example: EXM2A-02-512 = 2 MB flash + 512 KB SRAM)
• Flash Memory: Read-only operation; supports boot disk functionality
• SRAM Memory: Read/write capable; non-bootable disk operation
• Interface: EXM expansion interface, electrically similar to PC ISA bus
• I/O Registers: Module ID register at 100h (read-only); configuration registers at 102h and 103h (read/write)
• EXMID Decoder: Address 96h; enables per-slot EXM module selection
• Write Protection: Jumper JP1 controls flash reprogramming; factory default is write-enabled
• Expandability: Supports up to 8 modules per embedded PC

– Key Features

• Dual-memory architecture eliminates the tradeoff between persistent storage and dynamic access
• Boot-capable flash eliminates dependency on external storage media
• BIOS configuration program manages module detection and parameter initialization at power-up
• ISA bus compatibility enables use of standard PC software without custom drivers
• Hardware write-protection via jumper prevents unintended flash modification

– Typical Applications

• Embedded systems requiring persistent boot code and volatile working memory
• Rugged field-deployable platforms with limited expansion slots
• Industrial controllers and real-time systems needing fast storage access

– Compatibility & Integration

The EXM-2A integrates into any embedded PC supporting the EXM expansion interface standard. Formatting utilities and SRAM drivers are supplied on distribution media. The module’s ISA bus electrical compatibility ensures operation with most operating systems, though older chipsets may require specific drivers.