AR# 6057


M1 Map - ERROR:x4kma:7 - The CY4 symbol "$blah" has no signal connected to CIN


keywords : map, CY4, CIN, x4kma:7

urgency : standard

general description :

Map may produce the following error due to unconnected nets in a
design - especially for macros in the library whose CIN block is not

>Removing unused logic...
>ERROR:x4kma:7 - The CY4 symbol "$I1/$1I149" (output
>signal=$I1/C0) has no signal connected to CIN. This can
>only be done with carry-initiating carry modes (those that
>are not of the form xxxxx-CI). Please change the carry
>mode on this symbol to be a carry-initiating mode, or
>connect a CY4 with a carry-initiating mode to the CIN pin
>of "CY4 symbol "$I1/$1I149" (output signal=$I1/C0)".
>Errors were found in the carry logic. No output files have
>been written.


If you don't need the CIN block, it's important that it be tied
to a known value such as GND or VCC rather than leaving it
floating. In order to also avoid the propagation of optimization
during map, the GND or VCC plane should be separated by
a register from the CIN input. In other words, drive the CIN
input with an FD whose DIN input is tied to VCC or GND, as
needed. This will eliminate the error and any undesired
AR# 6057
Date 03/27/2000
Status Archive
Type General Article
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