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AR# 5732

1.5 XC4000XL Map - ERROR:x4kma:367 - An illegal carry configuration has been detected...


Express design with no RLOCs fails to pack Carry chain.

ERROR:x4kma:367 - An illegal carry configuration has been detected for CY4
symbol "C14254_C6_C2" (output signal=C14254_C6_cout0_net). The required
route-through cannot be performed because no more combinational pins are
available. Please check the F/HMAPs for defining the usage of this carry
comp (mapped physical logic cell).


This error appears to be related to the fact that Express does not RLOC any of the carry chains. Map
needed more guidance than it was getting apparently. I was able to get this design to map successfully
by adding the following RLOC attrubutes:

INST "C14254_C6_C2" RLOC = R0C0 ;
INST "C14254_C5_C2" RLOC = R1C0 ;
INST "C14254_C4_C2" RLOC = R2C0 ;
INST "C14254_C3_C2" RLOC = R3C0 ;
INST "C14254_C2_C2" RLOC = R4C0 ;
INST "C14254_C1_C2" RLOC = R5C0 ;
INST "C14254_C0_C1" RLOC = R6C0 ;

INST "FMAP_38" RLOC = R0C0 ;

The first seven attributes RLOC the carry chain. The last attribute pulls the problem FMAP into the appropriate CLB.
AR# 5732
Date 04/10/2000
Status Archive
Type General Article