02-13-2020 08:09 PM
I use the xc7k325t recover the LVDS data, but the LVDS source send the CLK with SSC, i use this clk multi 7 to capture the data, the data is wrong. my question:
1. dose DCM can passthrough the SSC to x7 clock?
2. how much ssc the DCM can deal with?
3. should i adjust the clk phase?
02-13-2020 09:13 PM
Since you are using Kintex-7 device, I am assuming that you are using MMCM and SelectIO.
It is mentioned in the datasheet that MMCM input clock jitter should be less than 20% of its period or 1ns at max.
You may need to check if the SSC value does not exceed this jitter spec.
Probably you could test your system with SSC disabled mode before doing any other test. (adjust clk/data delay etc)
02-15-2020 12:39 AM
thank you for your reply.
yes i am using MMCM and SelectIO.
it can work very well without ssc.
let me check the SSC value.
if the value exceed the 20%, do i need to adjust the clk/data delay? or the DCM can not work
02-16-2020 03:10 AM
>it can work very well without ssc.
That is good to hear.
>let me check the SSC value.
>if the value exceed the 20%, do i need to adjust the clk/data delay? or the DCM can not work
We can't guarantee MMCM will work with input clock jitter exceeds datasheet value.
# If input clock frequency is faster than 200MHz, jitter should less than 1ns.
Thanks & regards