The TMS34094 ISA Bus Interface device, a peripheral device for the TMS34020 Graphics Processor, facilitates the design of a high-performance graphics system for use in an ISA Bus-compatible PC. The device decodes ISA Bus cycles and controls the TMS34020 host interface to enable read and write accesses to the TMS34020's local memory. In addition, the TMS34094 allows the host to access the TMS34020's local memory via either I/O-mapped or memory-mapped ISA Bus accesses. The capability is software configurable, simplifying design and reducing system cost.