How to phase align a 10MHz clock using V4LX60 DCM

Jul 26, 2006 4 Replies

Hello, I am now working with new board based on ARM processor which is pluged on top of V4LX60 based board from avnet. But after the ARM board is manufactured it is observed that the clock from the ARM is delayed compared to the other signals. Since redesign of the board is not possible i thought to advance the clock by 4ns using the DCM on the V4 board. But the problem is the clock signal is only 10MHz frequency. Thus it is outside the frequency range (input clock) of the DCM if i am using the CLK0 output. Thus it is possible to use only the CLKFX output. But the minimum output frequency is 32MHz. Thus i thought to use two DCMs. One to multiply the input clock with 10 and will do a phase shift of 4ns. Then this will be divided by another DCM which will divide by 10 to get a phase advanced 10MHz frequency. But the problem observed is that the input 10MHz and the multiplied



100Mhz are phase aligned also the input to second DCM and the output
10MHz are also aligned. The First input and the output of the second DCM is not showing any relation ship. How can i tackle this problem

Hi I am Subins collegue, What we are trying to do is advance the input clock by 4 to 6 ns not to delay it.

pretty much the same thing, if you are considering that the delayed version, it's an "early" version against the next transition..., otherwise just wait for soeone to invent a time machine. Aurash

__ / /\/\ Aurelian Lazarut \ \ / System Verification Engineer / / \ Xilinx Ireland \_\/\/ phone: 353 01 4032639 fax: 353 01 4640324

Snort

The other possibility is to delay all the other signals on 1 metre of FR4. That'll advance the clock relatively by 6 nS ;)

Cheers

PeteS

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