cancel
Showing results for 
Search instead for 
Did you mean: 
Highlighted
Contributor
Contributor
246 Views
Registered: ‎02-24-2018

ZCU106 DDR PLL

Hi all, 

I found an error which is very weird. Like the attached picture, if I change this value over 533.5, it shows this error. Hence, what's the meaning that the range is [100, 800] shown in the picture neither. Does anyone have some ideas about this?WeChat Screenshot_20200514011028.png

Regards,

Crystal

0 Kudos
4 Replies
Highlighted
238 Views
Registered: ‎06-21-2017

Re: ZCU106 DDR PLL

What clock speed is used on your DDR setup page?

0 Kudos
Highlighted
Contributor
Contributor
232 Views
Registered: ‎02-24-2018

Re: ZCU106 DDR PLL

Dear @bruce_karaffa ,

You may check whether the attached picture is needed by you. BTW, the value 1067 can't be modified to a value more than 1067.WeChat Image_20200513230300.png

BR,

Crystal

0 Kudos
Highlighted
220 Views
Registered: ‎06-21-2017

Re: ZCU106 DDR PLL

If you are using DDR4-2133, your clock cannot be more than 1/2 of 2133, that is 1067.  If you want to use a faster clock, choose a faster RAM, 2400, 2633 or whatever you can buy.  RAM speed and availability change rapidly.  Check with a supplier before choosing.  Given a choice, pick a faster RAM.  It will probably go obsolete later than a slower one and can give you more timing margin. 

0 Kudos
Highlighted
Contributor
Contributor
215 Views
Registered: ‎02-24-2018

Re: ZCU106 DDR PLL

Dear @bruce_karaffa ,

I can understand the maximum freq. is 1067 Mhz. However, I can't understand why this value is halved using a PLL shown in the first picture, a.k.a why can't I achieve 800 Mhz or 1067 Mhz?

BR,

Crystal

0 Kudos