Alec Aivazis edited figures/lab_5-1/caption.tex  about 9 years ago

Commit id: 666b939e04e7e465f2a32c7634ce4f0432be7bd3

deletions | additions      

       

\label{fig:control}  This diagram shows the part of the circuit that is responsible for the logic driving the counter. The core of the controller is the finite state machine labeled \textit{stop} in the diagram. The state machine is responsible for causing the counter to begin counting from its current value as well as stopping the count. As shown in figure \ref{fig:fsm}, when the button goes high, the state machine switches between \textit{start} and \textit{stop}. In order to trigger the transition, the built in keys on the FPGA were hooked up a positive edge trigger which sent a short pulse to the state machine causing only a single transition \footnote{If the pulse is too long then it will still be high when the transition occurs causing another one.}. Since the keys on the FPGA are attached to built in debouncers, I did not have to bring one in from previous projects. The second button is attached to the clear of each counter and acts as a reset.