Abaco Systems / SBS / Bit 3 82902270 VMEbus Adapter with DMA Controller Module

The Abaco Systems / SBS / Bit 3 82902270 is a VMEbus adapter module with integrated DMA controller designed to enable high-speed data transfers between systems. The module provides transparent connectivity by mapping the address space of a destination bus into the host bus address space, allowing processor-efficient block data movement with minimal overhead.

Technical Specifications

• 32-, 16-, or 8-bit data transfers


• DMA Controller Mode and Slave Mode DMA operation


• Sustained DMA transfer rates up to 26 MBytes/sec (chassis to chassis)


• VMEbus DMA devices achieve transfer rates exceeding 12 MBytes/sec into VMEbus memory Addressing & Memory Mapping


• A16, A32, or A24 addressing modes


• Flexible mapping of remote VMEbus "windows" into local address space via jumper configuration


• Hardware mapping translates discontiguous remote addresses to contiguous local addresses


• Any memory or I/O space address supports memory mapping


• Direct C language pointer access to remote resources DMA Controller


• Reads data from one bus and writes to the other with processor interrupt upon completion


• Dual Port RAM support with arbitration handled on-card


• Optional shared memory up to 8 MBytes


• Dual Port RAM access requires no cross-bus access, enhancing security and limiting bandwidth use System Control Functions


• VME slot 1 system controller capability


• Provides VME system clock and system reset signals


• Four-level priority, four-level round-robin, or single-level bus arbitration


• Bus error global timeout protection Interconnect & Interrupt Handling


• Protocol-free connection with linked timing only during cross-system memory or I/O references


• Direct interrupt passing between buses


• All seven VME interrupts monitored and acknowledged from host system without polling

Key Features

• Transparent memory and I/O space mapping eliminates software complexity


• Processor overhead minimized through hardware DMA


• Optional Dual Port RAM for secure, isolated data access


• Complete VME system controller integration


• Bus arbitration flexibility supports multiple priority schemes

Typical Applications Chassis-to-chassis data movement, VMEbus system expansion, high-speed inter-system communication, and distributed processing architectures requiring transparent address space translation.

Compatibility & Integration Designed for VMEbus environments requiring both master adapter and system controller functions. Compatible with standard VME interrupt levels and addressing protocols.