Peripheral bus with continuous real-time control

摘要

A digital data processing system wherein large amounts of digital data are transferred from a source that is coupled to the internal bus of a host CPU to a data receiving device by cooperation between the host CPU and a microprocessor. A multiplexer has one of its input ports coupled to the host bus and its output port coupled by way of what is called a non-real-time bus to one or more devices that may be destinations for large amounts of data and need to be under at least periodic or non-real-time control by the microprocessor. Another bus, called a real-time bus, couples the microprocessor to another input port of the multiplexer. All digital devices that require real-time control by the microprocessor are coupled to the real-time bus. For data transfer, the microprocessor causes the multiplexer to couple the host bus to the non-real-time bus at which time the processor suspends control over the non-real-time devices but maintains control over the devices coupled to the real-time bus.