Bus driving and decoding circuit for validating the decoding of signals put on the bus by said drivers, comprising a plurality of driver elements and a decoder connected to the bus, the drivers being grouped in at least two sets, each implemented in one integrated component having a control input for enabling the opening of the related driver set, the control input receiving an enabling signal which is further input to one driver in each integrated component, so as to obtain at the output of the one driver a validation signal (V1, V2) for the decoder, each validation signal having an intrinsic delay equal to the propagation delay of the related integrated component, the circuit comprising further a delay element, located upstream or downstream of driver elements which generate the validation signals, to provide each of the validation signals with an incremental delay sufficing to cover the propagation delay spread specific to the related integrated component, the decoder being enabled by the joint assertion of the validation signals.
A pair of data processing systems, each of the data processing system having a host central processor and an associated controller including memory, both of the data processing systems to be cooperatively associated with a number of disk drive memory units, each of the disk drive memory unit coupled to both said controllers. Either one of the host central processors can appropriate any one of the disk drive memory units as a selected disk drive memory unit by propagating path-control-data to the memory in both of the controllers and in the selected disk drive memory unit.
A method for ensuring proper strobe pre and post driving between a first data transfer and a second data transfer in a microprocessor system. The method includes generating a first strobe signal and a second strobe signal, pre-driving one of said first and second strobe signals before the first data transfer, post driving said pre-driven signal, determining which of said first and second strobe signals will be post driven, and pre-driving one of said first and second strobe signals before the second data transfer.
A semiconductor multi-device system incorporated on a single semiconductor chip is disclosed including a central processing unit, a bus, a plurality of peripherals, a plurality of on-chip data bus drivers connected to selected lines of the bus, and logic means for controlling the operation of the on-chip data bus drivers. The multi-device system of the invention is capable of interacting with off-chip components including an off-chip processing unit and off-chip peripherals. The off-chip components may also include a plurality of off-chip data bus drivers that drive data signals onto and off of an off-chip data bus. The on-chip and off-chip drivers must cooperate in order for data signals to transfer properly between the on-chip and off-chip components. The logic means of the invention is designed so as to minimize the logic necessary to cause the on-chip drivers and the off-chip drivers to cooperate properly. The logic means of the invention is also designed to function properly regardless of whether the on-chip processing unit or the off-chip processing unit is in control of the overall system comprising both on-chip and off-chip components. The logic means is also designed to control the operation of the on-chip drivers in a simple and efficient manner. Thus, a multi-device system is disclosed which is a significant improvement over those of the prior art.
