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AR# 2363

1.5i MAP: How can I estimate the total number of packed CLBs in my design?


Keywords: CLB, FMAP, LUT, MAP

Urgency: Standard

Reference: 14619

General Description:
The number of PACKED CLBs required by a design gives the user
an idea of how many CLBs would be required if the Mapper were
to pack the logic into the CLBs for maximum density. (Note
that doing this can adversely affect the routability of the

The M1.3 mapping report does not report this parameter.
It only reports the number of LUTs, Flip Flops, Latches,
and occupied CLBs needed by the design.


If the number of LUTs (FMAPs) is greater or equal to the total
number of flip flops and latches, a close enough approximation of the number of PACKED CLBs can be obtained by dividing the
number of 4-Input LUTs by two:

Number of packed CLBs = (4_Input_LUTs) / 2

Alternatively, if the total number of non-IOB latches and flip
flops is greater than then total number of LUTs then use the
following formula:

Number of Packed CLBs = (Flip Flops + Latches) / 2
AR# 2363
日期 03/27/2000
状态 Archive
Type 综合文章