IEEE 959-1988

One of the most important parts of any computer system is the I/O. Many systems require different types of I/O depending on the specific application. In addition, the system designer is faced with a significant challenge to keep up with new technology in I/O devices types, interfaces, and the LSI components designed to support them. The IEEE 959 I/O expansion bus is designed to address these needs. Using this standard interface allows small increments of I/O to be added or modified in an easy, cost-effective way. The IEEE 959 I/O expansion bus is specified independent of processor or board type. Each expansion interface supports up to sixteen 8-bit I/O ports directly. Enhanced addressing capability is available using slave processors or FIFO devices. In addition, each expansion interface may optionally support a DMA channel capable of data rates up to 2 16-bit Mwords/sec. These features are supported for both 8- and 16-bit data paths. This specification has been prepared for those users who intend to design or evaluate products that will be compatible with the IEEE 959 I/O expansion bus. For this purpose, functional, electrical, and mechanical specification are covered in detail. The intent of the specification is to guarantee compatibility between baseboards and expansion modules while not restricting the actual designs any more than necessary. Additional design considerations that are not part of the actual specification are presented in the appendixes.



New IEEE Standard - Inactive-Withdrawn. An I/O expansion bus for microcomputers that is independent of processor or board type is specified. Each expansion interface supports up to 16 8-bit I/O ports directly. Enhanced addressing capability is available using slave processors or FIFO devices. In addition, each expansion interface may optionally support a DMA channel capable of data rates up to 2 16-bit Mwords/sec. These features are supported for both 8- and 16-bit data paths. The specification has been prepared for those users who intend to design or evaluate products that will be compatible with the bus. For this purpose, functional, electrical, and mechanical specification is covered in detail. The intent of the specification is to guarantee compatibility between baseboards and expansion modules while not restricting the actual designs any more than necessary.