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
Data Transfer Modes
• 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.
