Programmable Devices
CPLDs, FPGAs, SoC FPGAs, Configuration, and Transceivers
Announcements
The Intel sign-in experience has changed to support enhanced security controls. If you sign in, click here for more information.
20002 Discussions

User IO pin vs PLL_CLKOUT0N pin. Can I output a clock on user IO?

JDeff
Beginner
661 Views

What is the difference between the CLKOUT pins and user IO pins? The fitter allows routing of a pll clock output to a user IO pin. What is the difference? Will I get better performance or timing closure if I use the dedicated clkout pin? Right now I am using a single ended clock and its routed to a IO pin, but I am getting poor results and timing closure problems. Wondering if it is worthwhile to spin the board to use a dedicated clkout pin.

0 Kudos
1 Solution
JonWay_C_Intel
Employee
333 Views

The clkout is a dedicated path from the PLL to output pin. In zero delay buffer mode, the delay by the output pin is compensated. https://www.intel.com/content/www/us/en/programmable/documentation/mcn1401782837027.html#mcn1401869677350

 

The fitter allows your PLL to output to user io pin via global routing.

 

Will you get better performance? To find out, you will need to analyze timing given the PLL compensation mode and routing to the clkout pin.

View solution in original post

1 Reply
JonWay_C_Intel
Employee
334 Views

The clkout is a dedicated path from the PLL to output pin. In zero delay buffer mode, the delay by the output pin is compensated. https://www.intel.com/content/www/us/en/programmable/documentation/mcn1401782837027.html#mcn1401869677350

 

The fitter allows your PLL to output to user io pin via global routing.

 

Will you get better performance? To find out, you will need to analyze timing given the PLL compensation mode and routing to the clkout pin.

Reply