AR# 4419: M1.4: Map FATAL_ERROR:baste:bastetspec.c:2402:1.69.14.3 - NET OFFSET 'IN1 IN : 20000.00 pS : BEFORE : CLK' has no data IOBCOMP.
AR# 4419
M1.4: Map FATAL_ERROR:baste:bastetspec.c:2402:1.69.14.3 - NET OFFSET 'IN1 IN : 20000.00 pS : BEFORE : CLK' has no data IOBCOMP.
Description
Keywords: Bastetspec, NET OFFSET, IOBCOMP,map, timespec, xc5200
Urgency: standard
General Description
When running a XC5200 design through M1.4, you may get following map error:
FATAL_ERROR:baste:bastetspec.c:2402:1.69.14.3 - NET OFFSET 'IN1 IN : 20000.000000 pS : BEFORE : CLK' has no data IOBCOMP. Process will terminate. Please call Xilinx support.
Solution
This is could be due to a bug in Map. This is currently scheduled to be fixed in M2.1.
The workaround is not to use OFFSET timing constraint. Instead, use FROM:TO timespec. For example comment out the OFFSET constraint and add the last two lines:
NET clk PERIOD = 40 ; //NET "IN1" OFFSET = IN 20 before "CLK"; <== DO NOT USE
For OFFSET IN, the pad to flop delay is reduced by the pad to clk delay. The user must manually adjust for this when using a FROM:TO. If the user chooses not to adjust the delay, the FROM:TO is overly conservative.
For OFFSET OUT, the flop to pad delay is added to by the pad to clk delay. The user must manually adjust for this when using a FROM:TO. If the user chooses not to adjust the delay, the FROM:TO is not conservative enough.