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AR# 10266

Virtex-E/Spartan-IIE CLKDLL - Can I obtain additional IBUFGs to access DLLs on the chip (IO_LVDS_DLL, IBUFG)?

Description

I need more than four IBUFGs to access CLKDLL in my Virtex-E or Spartan-IIE chip, but there are only four IBUFGs available. Is there anything I can do to obtain additional dedicated access to the DLLs?

Solution

Additional dedicated access to the DLLs can be obtained by using the dedicated pins called "IO_LVDS_DLL."  

 

- Instantiate four IBUFGs inside your design. 

 

- For the signals that need additional IBUFG, connect IBUFs between the signals and the DLL.  

 

- Then, lock these signals to the IO_LVDS_DLL pins (see package pin-outs for the pin numbers) for the DLL you want to use.

AR# 10266
Date Created 08/29/2007
Last Updated 05/07/2014
Status Archive
Type General Article