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How to synchronize the two clocks running at different freq?

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gowrimaharaja

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How to synchronize the two clocks running at different freq?
 

Fom

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Re: How to synchronize the two clocks running at different f

If difference is small it is impossible to synchronize them.
Or do you mean one of this frequency can be tuned by external signal?
 

liujingshu

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Re: How to synchronize the two clocks running at different f

My experience is you shoulde constrate on the code. You should stagger the two clocks.
 

silencer3

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use two flops as synchronizing flops when siganls cross from clock domain to another clock domain. This ensures that the signals is latche proeprly with second clock. this also ensures the metastable (which generally occurs in these situations) aviodance.
 

Nandy

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Re: How to synchronize the two clocks running at different f

If you are talking about one clock system receving data generated by another asynchronous clock. You can use aynchronous FIFO. If only one bit handshake signal involved, you can use level synchronizer or pulse-synchronizer.

Nandy
www.nandigits.com
Netlist Debug/ECO in GUI mode.
 

cheelgo

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Nandy tool is good at ECO? I will have a look, thanks nandy.
 

Nandy

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Re: How to synchronize the two clocks running at different f

Hi cheelgo

Yes. GOF, Gates-On-the-Fly, is a graphical netlist Debug/ECO tool. I am one of the designers. Let me know if you have any questions.

Thanks.

Nandy
www.nandigits.com
Netlist Debug/ECO in GUI mode.
 

jelydonut

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Re: How to synchronize the two clocks running at different f

i didn't truely understand the question..

but i agree with silencer 3..

if you want to sync to a clock you hafta use flops to cross the clock domain..

jelydonut
 

haytham

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Re: How to synchronize the two clocks running at different f

Use synchronizers when you a signal is crossing the clock boundaries
 

mystique_unbound

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Re: How to synchronize the two clocks running at different f

A synchroniser circuit used as an intermediate between the two flops (different frequencies). This synchroniser circuit can be modelled using two latches one enabled using clk1 and other being enabled by clk2 . Also variable frequency will affect your hold time constraint drastically if second flop is a t high frequency than the first .
 

Resistance

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Re: How to synchronize the two clocks running at different f

hi ,
Actually can tell me whether u working in the bread board or in the synthesis segment on a EDA tool..

Anyway the concept is not to unnecessarily optimze the path u have designed between two flops by the tool.. U are in look out for commands do tell i will mail that.

u can use synchroniser circuit constituting latches.. but jus follow the path carefully including all the possible combination paths also and compute timing manually not to violate set up and hold time..

regards.
 

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