UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Visitor forsa
Visitor
4,552 Views
Registered: ‎01-24-2011

"S/R recovery before clock" (tRAI) for Coolrunner II

Jump to solution

I am reading the Timing Model in DS090 for Coolrunner II, but I can't find the "Register asynchronous S/R recovery before clock" (tRAI)  

 

Is it not applicable anymore?  

Tags (1)
0 Kudos
1 Solution

Accepted Solutions
Visitor forsa
Visitor
5,144 Views
Registered: ‎01-24-2011

Re: "S/R recovery before clock" (tRAI) for Coolrunner II

Jump to solution

Solved. This is the answer from helpdesk:

 

We dont have a Trai value for the Coolrunner-II. But the "safe to use" value for Trai would be to copy the Taprpw for the density/speed grade.

View solution in original post

0 Kudos
2 Replies
Highlighted
Visitor forsa
Visitor
4,521 Views
Registered: ‎01-24-2011

Re: "S/R recovery before clock" (tRAI) for Coolrunner II

Jump to solution

 

The reason I am asking is that I'm porting code from a XC9500 to a Coolrunner 2 (XC2C128-7)

 

The design includes a VME bus slave, where the interface is designed asynchronously. The data strobe input is fed to the S/R pin of a FF, while a delayed version of this strobe signal is fed to the clock input of the same FF. 

 

The Clk input needs to be sufficiently delayed so that the FF has time to recover after the reset (the clock edge cannot occur instantly after releasing the reset due to tRAI). 

 

The reset recovery time (tRAI) is 10 ns for the XC95144XL-10 

http://www.xilinx.com/support/documentation/data_sheets/ds056.pdf

 

but I can't find the tRAI for my XC2C128 here:

http://www.xilinx.com/support/documentation/data_sheets/ds093.pdf

 

 

Why? Am I missing fundamental changes to the architecture?

 

Best Regards, 

Steffen Forså

0 Kudos
Visitor forsa
Visitor
5,145 Views
Registered: ‎01-24-2011

Re: "S/R recovery before clock" (tRAI) for Coolrunner II

Jump to solution

Solved. This is the answer from helpdesk:

 

We dont have a Trai value for the Coolrunner-II. But the "safe to use" value for Trai would be to copy the Taprpw for the density/speed grade.

View solution in original post

0 Kudos