Answers Database
MAP M1.4: x4kma:312 - The following symbols could not be constrained to a single CLB (Two F-LUT's, an H-LUT, and carry logic).
Record #3766
Product Family: Software
Product Line: FPGA Implementation
Product Part: map
Product Version: 1.4
Problem Title:
MAP M1.4: x4kma:312 - The following symbols could not be constrained to a single CLB (Two
F-LUT's, an H-LUT, and carry logic).
Problem Description:
Urgency: Standard
General Description:
This solution record involves one case where the following
error message is encountered during MAP.
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ERROR: x4kma:312 - The following symbols could not be
constrained to a single CLB:
CY4 symbol "$1I243" (output signal=C6)
CY4_12 symbol "$1I196" (output signal=$1N232)
FMAP symbol "$1I221" (output signal=S6)
HMAP symbol "$1I345" (output signal=S7)
FMAP symbol "$1I222" (output signal=S)
There are two resources that require the F function
generator. These symbols share the same RLOC attribute value,
which requires them to be mapped to the same CLB.
-----
In this specific case, all three lookup tables and the carry
logic are being utilized. The carry mode is ADDSUB. The CIN
input is driven and also goes to the F-LUT. The carry goes to
the G-LUT. The F-LUT utilizes all four inputs and the output
goes out of the CLB. The G-LUT uses all four inputs. The
H-LUT has all three inputs driven: one comes from the output
of the G-LUT, and the other two from outside the CLB. The
H-LUT output goes out of the CLB.
This looks to be a legal pack.
Solution 1:
MAP M1.4 cannot perform this legal CLB pack.
It has been addressed and fixed for the next Core Tools
release, M1.5.
End of Record #3766 - Last Modified: 04/30/98 14:39 |
