Abstract: An asynchronous circuit utilizes toggle flip-flops to receive a plurality of asynchronous input signals. The input signals are applied to the edge-triggered clock inputs of the toggle flip-flops so that outputs of the toggle flip-flops and other logic signals within the asynchronous circuit change with respect to particular edges of the input signals. An output signal is responsive to the changes in the outputs of the toggle flip-flops and is thus responsive to the changes in the asynchronous input signals. Since the input signals have well-defined transitions which cause the changes in the output signals, various parameters, such as propagation delays, can be measured and characterized. The asynchronous logic circuit thus provides the operational advantages of asynchronous circuits while exhibiting the testability characteristics of clocked logic circuits.