Answers Database
2.1i Virtex Map - Map errors atttibuted to incorrect CLKDLL usage (ERROR:xvkmm:12 and ERROR:xvkmm:16)
Record #6624
Product Family: Software
Product Line: FPGA Implementation
Product Part: map
Product Version: 2.1i
Problem Title:
2.1i Virtex Map - Map errors atttibuted to incorrect CLKDLL usage (ERROR:xvkmm:12 and
ERROR:xvkmm:16)
Problem Description:
Urgency: Standard
General Description:
ERROR:xvkmm:12 - CLKDLL is driven by AND2 symbol "$I9"
(outputsignal=$Net00010_), the only valid components to drive
CLKDLL is IPAD, IBUFG or BUFG.
ERROR:xvkmm:16 - BUFG symbol "$I17" (output signal=$Net00004_)
driving CLKDLL must be driven by CLKDLL too.
The first error implies that the CLKIN input of the DLL is being sourced
by internal logic directly which is an illegal setup.
The second error implies that the CLKIN input, even though being
sourced by a BUFG is still in error because the input of the BUFG
comes from some internally sourced logic.
Solution 1:
The CLKIN input of the DLL is not meant to be internally sourced.
The CLKIN input can either be sourced by an IBUFG (i.e. and
external signal) or a BUFG that is sourced by a CLKDLL itself
(i.e. in the case of using the CLKDLL in a DLL deskew setup
as shown in XAPP 132).
Please refer to XAPP132 for more details:
http://www.xilinx.com/xapp/xapp132.pdf
End of Record #6624 - Last Modified: 10/07/99 12:46 |
