Abaco Systems / SBS 800-202 VME64 Bus Adapter with DMA

The Abaco Systems SBS 800-202 is a 6U VMEbus card that bridges two VME64 buses into a unified system with direct memory access capabilities. It delivers controller mode DMA transfers at 70 MB/s and enables transparent memory/I/O mapping of remote bus address space to local address ranges without protocol overhead. The adapter supports fiber-optic cable connectivity up to 500 meters, making it suitable for distributed VME architectures requiring low-latency inter-bus communication.

Technical Specifications

• Controller mode DMA: 70 MB/s


• DMA block transfers up to 16 MB with 8 register write commands


• Configurable block size: 4 to 16 MBytes


• Supported data widths: D32, D16 Latency Characteristics


• Across-cable latency: 1.8 µs


• VME to Dual Port RAM latency: 4 µs


• Transaction latency: 2 µs Memory Architecture


• Optional Dual Port RAM: 128 KB or 8 MB


• A32/A24 addressing to Dual Port RAM


• Discontiguous-to-contiguous memory mapping hardware


• 32-, 16-, and 8-bit data access widths to Dual Port RAM Connectivity & Addressing


• VME64-to-VME64: 64-, 32-, 16-, or 8-bit data; A32 addressing


• PCI-to-VME64 and VME64-to-PCI: A32, A24, A16 addressing


• Cable interface: Fiber-optic up to 500 meters


• Streamlined, protocol-free connectivity Bus Management


• Bi-directional bus mastership


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


• Can function as VME slot 1 system controller (clock, reset, bus error timeout)


• IRQ1-7 plus two programmable interrupts passed across cable


• Dedicated error interrupt for adapter status monitoring

Key Features

• Transparent address mapping eliminates protocol stack overhead


• Dual Port RAM provides electrical isolation and bandwidth limiting per accessing bus


• All seven VME interrupts monitored and acknowledged from host


• IEEE 1014C compliant

Typical Applications Distributed real-time VME systems, long-distance bus bridging, low-latency inter-chassis communication, applications requiring transparent memory access across geographically separated VME domains.

Compatibility & Integration Full IEEE 1014C VME64 compliance. Operates 0° to +60° C. Requires 2.5 A at 5V and +3.3V DC.