Kevin Weddle
- Feb 23, 2004
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You want asynchronous when the time is not crucial and you want a minimum number of devices. Use synchronous when the time is crucial but will require more devices. There is a minimum amount of time delay between devices when using synchronous.
Hi all.
well Kevin it is not exactly like that.
Normally you build counters using flip flops. According to how you will connect the clocks of your flip flops, you can get a sync. or an async. counter. You have a syncronous counter when all clock inputs of the flip flops are connected to a single, common clock. An asynchronous counter uses each flip flop's clock differently. You may want to take a look at this page for more details and some examples:
http://www2.ele.ufes.br/~ailson/digital2/cld/chapter7/chapter07.doc5.html
As for advantages and disadvantages, each counter fits in different applications and therefore I don't think you could make a comparison between them. In general you put sync. counters in synchronous systems and asynchronous in async. systems (these are the faster ones btw., but are more complex to design)
well Kevin it is not exactly like that.
Normally you build counters using flip flops. According to how you will connect the clocks of your flip flops, you can get a sync. or an async. counter. You have a syncronous counter when all clock inputs of the flip flops are connected to a single, common clock. An asynchronous counter uses each flip flop's clock differently. You may want to take a look at this page for more details and some examples:
http://www2.ele.ufes.br/~ailson/digital2/cld/chapter7/chapter07.doc5.html
As for advantages and disadvantages, each counter fits in different applications and therefore I don't think you could make a comparison between them. In general you put sync. counters in synchronous systems and asynchronous in async. systems (these are the faster ones btw., but are more complex to design)
Kevin Weddle
- Feb 23, 2004
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What do you mean it's not exactly like that. Your explaination is identical to mine.
surajbarkale
- Aug 5, 2004
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In a synchronus counter, all flip-flops have same clock signal. Thus the outputs of all flipflops change at same time. However a asynchronus counter dosen't has a single clock going to all ff's thus creating glitches in the output. Although asynch counter can be built with vrey little glue logic, it it not advisable at high frequency.
