Bidirection data switch sequencing circuit

DETAILED DESCRIPTION What is claimed is: 1.
In a circuit having at least two port means for sending and receiving signals, said port means being coupled to one another by bidirectional gating means for providing, in response to an enabling signal, a signal path in one of two selectable directions, the direction of said signal path depending on a steering signal, and first and second signal source means for respectively producing a gating signal and a direction indicating signal, the improvement comprising: asynchronous circuit means for producing said enabling signal and said steering signal in response to said first and second signal source means, said asynchronous circuit means including means for inhibiting said enabling signals until said steering signal is established.
2.
The invention as claimed in claim 1 wherein said asynchronous circuit means further includes means for discontinuing said enabling signal if said direction indicating signal changes and for continuing said steering signal until said enabling signal is inactive.
3.
The invention as claimed in claim 2 wherein said asynchronous circuit further includes means for reactivating said enable signal when said steering signal has been established in the second direction.




Description:
DESCRIPTION TECHNICAL FIELD This invention relates to signal sequencing circuits and particularly to the proper sequencing of controlling signals to bidirectional data switching circuits.
When bidirectional data switching circuits are used, two signals are required to control their operation.
One signal is a direction indicating signal which determines the direction the data is to be passed through the bidirectional switch circuits.
The second signal is an enabling or gating signal which causes the data to be switched.
It is usually essential that the directional signal be stabilized before the gating signal is applied and that the directional signal not change during the gating signal's application.
Otherwise, the signals on the bus become uncertain and anomalous