How to transfer multiple bit data between phase shifted clock?

Different phases of the same clock are not asynchronous. There is a defined timing relationship between clk and clk_90 in your case, right? If the dat a can propagate between the two phases within that time (less setup), then you can just transfer the date directly between registers clocked by each p hase with no problems.

If the time is not long enough, there are other choices:

You have four clock edges total. You can use more than just the initial and destination edges in your transition, and you don't have to do it all at o nce. Assuming clk_90's rising edge is a quarter period after clk's rising_e dge:

You could transfer from rising_edge(clk) to falling_edge(clk_90) in 3/4 per iod), and then to rising_edge(clk_90) in 1/2 period.

Or you could transfer from rising_edge(clk) to falling_edge(clk) in 1/2 per iod, and then to rising_edge(clk_90) in 3/4 period. Either of these allows at least a half clock period to propagate the data in each step.

If you cannot make the transition in half a clock period (really fast clock !), you could transition in three steps: From rising_edge(clk) to falling_e dge(clk_90), then to falling_edge(clk), and finally to rising_edge(clk_90). Each of these are 3/4 period transfers.

As long as the tool understands the timing relationship between the two rel ated clocks, it will correctly analyze the timing on transfers between them , and report any problems.

Andy

Hi Andy,

Thank you very much for your quick reply.

Frequency of both the clocks are 100Mhz. So data should be stable before

If its not working then I can try other alternatives as you suggested.

Thanking you,

Krupesh

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Hi Andy,

I can successfully transfer data between clk and clk_90 clock without getting any timing violation or CDC warnings.

Thanking you,

Krupesh.

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allows

--------------------------------------- Posted through

Hi Andy,

I can successfully transfer data between clk and clk_90 clock without getting any timing violation or CDC warnings.

Thanking you,

Krupesh.

it

then

each

at

allows

--------------------------------------- Posted through