What's different between Flow chart and State diagram - Page 1
Forum section: electronics / general

author: Chirawat
author_rank: Newbie
timestamp: August 29, 2013, 02:47:50 pm
content: Hello,This is my first topic in EEVblogToday I wanna ask you about what's different between flow chart and state diagram. In my mind, it's very similar to each other.Could you explain me about idea of these?BR,Nott (from Thailand)

author: grumpydoc
author_rank: Super Contributor
timestamp: August 29, 2013, 03:06:24 pm
content: They are totally different.A flow chart documents a set of logical steps and decisions along a time line.A state diagram documents the various states in which a system can exist and the triggers and transitions between them.

author: TerminalJack505
author_rank: Super Contributor
timestamp: August 29, 2013, 06:06:56 pm
content: Both types of diagrams have the concept of 'flow' but state machine diagrams emphasize state. 'Flow' in a state diagram is always from state to state (or out of the diagram.) State machine diagrams describe a (typically) closed system composed of discrete states. The 'state' in this case determines how a system behaves to stimulus or events.The system described by a state diagram (a finite state machine) can behave completely differently to the same events depending on which state it is in. Because of this, the system has a kind of 'memory' due to how it moves from state to state. (See some of the examples I've attached.)On the other hand, a flowchart, I would say, emphasizes procedure. And, unlike a state machine diagram, there isn't a concept of state. The 'flow' of a flowchart is of a process. A flowchart shows the steps and actions to achieve a goal.Note that I used the term 'system' here but really should have used either the term 'subsystem' or 'entity'. State machine diagrams and flowcharts don't apply only at the system level. They can describe smaller pieces of an overall system.Two of the examples of state diagrams that I've attached describe a system-level state machine. (The Killectric III and the digital clock.) The other example is at the complete opposite end of the spectrum. It describes just one particular component of a system. (The rotary encoder.) A system can be composed of many of these.

author: Chirawat
author_rank: Newbie
timestamp: August 30, 2013, 02:26:27 am
content: Many thanks to grumpydoc and TerminalJack505.

author: TerminalJack505
author_rank: Super Contributor
timestamp: August 30, 2013, 02:40:04 am
content: No problem.I was going to make a YouTube video about finite state machines at one time. I never got around to making it but that's where those diagrams came from.State machines are useful for digital electronics (CPLDs, FPGAs, 74xx, etc.) as well as microcontrollers. Flowcharts aren't too useful for digital electronics, so far as I know. They're great for microcontrollers, though, due to their sequential nature.

author: Chirawat
author_rank: Newbie
timestamp: August 30, 2013, 09:07:13 am
content: Quote from: TerminalJack505 on August 30, 2013, 02:40:04 amCheers, I'm looking forward to watch your tutorial

author: magicsmoke
author_rank: Regular Contributor
timestamp: September 07, 2013, 05:20:10 am
content: Quote from: TerminalJack505 on August 29, 2013, 06:06:56 pmYour drawings look very professional what did you use to make them? Visio or something else?

author: TerminalJack505
author_rank: Super Contributor
timestamp: September 07, 2013, 05:31:19 am
content: Quote from: magicsmoke on September 07, 2013, 05:20:10 amThose were made with OpenOffice Draw, believe it or not. It's temperamental but does the job if you're persistent enough.