DCM.

"im.de" schrieb im Newsbeitrag news: snipped-for-privacy@o13g2000cwo.googlegroups.com...

I dont think multiply = 1 is valid, the smallest is 2 so you need to use M=2 D=4

otherwise what you did looks correct, we do it same way and it works (but we use valid M and D params of course)

Antti

im.de napisa³(a):

Is that any special needs to use DCM? If I were You I would use just flip-flop. It'll be faster for lock - instant, and 50%-50% low-high.

If you must use DCM, make it like Antti Lukats wrote.

Best regards

Jerzy Gbur

Or you can use just DLL part of DCM that will give you a fixed divided output clock @ 1/2 ofinput clock.

-James

I think that the problem is in multiply settings, as the minimum value of M is 2. But did not you get a warning in the synthesis about this?

Vladislav

All good advice:

Use the CLKDV output with DV=2 (divide by 2)

That is using the DLL part of the DCM, and it will have less jitter than using the CLKFX output with M=2, D=4 (M=1 is not a valid choice).

If you use the CLKFX to do this, be aware that the min frequency now applies to the output (CLKFX must be greater than 24 MHz, or whatever the min freq spec is for the part).

Austin