Asynchronous
Circuits - Classes
18/3/2014
CE-653 - Hazards and Analysis
Methods
5
}Dimension 1: Delay
Model
}Measure of robustness of control to variations in delays of
gates and wires
}Assumption about delays of gates necessary to ensure design
works as dictated by specification
}Most robust = Arbitrary
gate and wire delay
¨Design will work as
specified even if delays are random(0,infinity)
¨Larger delays just means
control is slower
}Least robust = Bounded
delay on gates and wires
¨If delays are outside
these bounds, glitches may occur at outputs or output simply may not
transition as expected
}Dimension 2:
Environmental Model
}Essentially these are assumptions/restrictions on how fast
environment can be for circuit to work