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STATE MACHINES

by Ingo Cyliax

Start ý An ASM Example ý Input and Output Signals ý Implementation ý One-Hot Encoding ý Synthesize ý Initializing ý Until Next Time ý Sources and PDF

AN ASM EXAMPLE

Letýs look at an ASM example so you can get a feel for it. Figure 1 shows a simple state machine. It has an input that is either left, right, or off. The first state of the machine is an idle state. The machine will cycle in this state while the input is off. After the input goes to left or right, the ready indicator will come on and either the left or right indicator will turn on (depending on the input) and stay on until turned off.

Figure 1ýHere you see an Algorithmic State Machine (ASM) chart that shows a simple machine. All of the outputs and inputs are symbolic at this point.

This example illustrates that you can write down an ASM chart from a verbal description. Notice that I have not specified any encoding because I donýt really know yet what the architecture is like. At this point, you could write a small program from this ASM to model or simulate your machine before you have any ideas about the architecture.

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