North American Philips Corporation

North American Philips Corp, Signetics Division

North American Philips Corp., Signetics Div.

Charles E Dike

Farrell Lynn Ostler

Edward A Burton

Thomas D Fletcher

An arbiter provides at an output a priority signal that indicates which one of the input signals at an input has gained priority over all other ones. The arbiter comprises a signal processing path between the input and the output for determining the priority signal. The arbiter further comprises a control means coupled to the signal path for detecting (rare) conflicts among priority candidates. In response to the detected conflict, the control means generates control signals to modify the signal path. This conflict-solving part of the arbiter is located outside the signal path. Accordingly, a signal propagation delay in the path is largely independent of the number of input signals.

Arbiter with a direct signal path that is modifiable under

A multiple-input arbiter first mutually correlates groups of input signals for identifying a particular group, which includes at least one input signal that is a candidate for gaining the overall priority. Thereupon the priority winner is determined in that particular group. Such a hierarchical processing lends itself to an architecture wherein the processing in groups is implemented by cascaded levels of uniform logic blocks. The decomposition in uniform logic blocks considerably simplifies the design of arbiters that process large numbers of input signals.

Arbiter with a uniformly partitioned architecture

An arbiter based on pairwise mutual exclusion produces an absolute priority signal (G) indicating that one of three or more requests (R.sub.1, R.sub.2, . . . R.sub.N) has gained absolute priority over all the other. At least one mutual-exclusion element (20.sub.1 or 20p) in the arbiter is designed so that its pairwise priority determination car be reversed in response to at least one externally originated test signal (T.sub.1, T.sub.2 or T.sub.M-1, T.sub.M). By doing so after the requests have been asserted in a specified order, a priority conflict can be generated among the requests in order to check the conflict-resolution capability of the arbiter.

Arbiter with test capability and associated testing method

A D-type flip-flop arrangement includes first and second latches .Circuitry interposed between the latches blocks any metastable condition that may occur in the first latch from propagating into the second latch. Additionally, the arrangement minimizes the likelihood that the first latch will enter a metastable condition and, if it does, resolves the condition extremely rapidly.

Metastable-immune flip-flop arrangement

A high-speed low-power-consumption two-input arbiter circuit comprises two input inverters, two inverters cross-coupled to form a latch and two additional inverters that drive a difference detector. The detector responds only to a voltage difference on its inputs that exceeds a specified value. In this way, signals are blocked from appearing at the outputs of the detector while the latch is in a metastable state. Additionally, an n-input arbiter circuit comprises (n-1)+(n-2)+ . . . +[n-(n-1)] two-input arbiter circuits and logic circuitry connected to the outputs of the two-input circuits for supplying a priority signal to one and only one at a time of n output terminals of the n-input circuit.

Arbiter circuits with metastable free outputs

A voltage translator containing a bipolar transistor (Q1), a rectifier (10), a resistor (R1), and a first clamp (12) converts an input voltage (V.sub.I) into one or more output voltages of restricted voltage swing. The first clamp clamps the emitter voltage of the transistor when it is turned on. In one version, the translator includes a second clamp (14) that clamps the collector voltage of the translator when it is turned off. The translator then provides an output voltage (V.sub.O) inverse to the input voltage. In another version, the first clamp is connected between a voltage supply (V.sub.EE) and the emitter of the transistor. Its collector is connected directly to another voltage supply (V.sub.CC) so that the translator only makes non-inverting translations.

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Pleasant Grove, UT, United States of America

Charles E Dike