Edge detection of a lo freq Clock using another high freq Clock

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imbichie

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Hi All,

Is it good to sample a Low Freq Clock (10 Mhz) with a High Freq Clock (87 Mhz).
The aim is to find the edge of the 10 Mhz clock and reset a counter which is running in 87Mhz.
Here the clocks are out of phase, and not a proper multiple.
So what i did was sample the 10 Mhz with the 87 Mhz,
is it synthesis or is it a good practice?
 

You will need to use a synchronizer on your 10MHz clock. Then apply an edge-detect circuit to your synchronized signal.
 

yes, there is no issue, you sample two times the 10MHz signal with the 87MHz signal, to avoid meta-stability and then you used this sample signal to detect an edge.
 

You could connect the 10MHz clock to the data input of the flop clocked with the 87MHz, there is no issue.
The clock tree tool will stop the 10MHz properly.
 

The clock tree tool will correctly equilibrate the tree.
 

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