Answers Database

M1.4 XC3000/3100: The signal "<signal between ipad and bufg>" is unused and has been removed.


Record #3519

Product Family:  Hardware

Product Line:  3100A

Problem Title:
M1.4 XC3000/3100: The signal "<signal between ipad and bufg>" is unused
and has been removed.



Problem Description:
Keywords: 3000A, 3100, 3100A, bufg, gclk, unused, removed,
trimmed, logic, global, buffer, clk, clock

Urgency:  Standard

General Description: M1.4:  In a XC3000 family part, logic is
removed that appears to be connected properly.	The map report
(map.mrp) lists logic removed similar to:

The signal "$1N24" is unused and has been removed.
 Unused block "$1I12" (IPAD) removed.
The signal "$1N28" is unused and has been removed.
 Unused block "$1I7" (OBUF) removed.
  The signal "Q_BUFG" is unused and has been removed.
   Unused block "$1I4/$1I37" (FDCE) removed.
    The signal "CLK_BUFG" is unused and has been removed.
     Unused block "$1I2" (BUFG) removed.
Unused block "$1I9" (OPAD) removed.

A BUFG appears as one of the last items removed.

Both BUFG and either ACLK or GCLK are used in the design.


Solution 1:

The XC3000 family may use either all BUFGs or ACLK and GCLK,
but not both in the design.

The mapping software has trouble converting the BUFG to the unused clock buffer.


Use only    BUFG   OR	xCLK	as your global buffers.



End of Record #3519