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Old 04-12-2006, 04:46 PM
Ray Andraka
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Default Re: To use adder and multiplier of DSP48 in V4

vssumesh wrote:
> Hi all,
> Is it possible to use the adder and multiplier in the DSP48 block of
> the virtex4 FPGA separately but simultaniously. From the user guide i
> get a feeling "No" but i wanted to know your expert openion on this
> issue.
> Thanks and regards
> Sumesh V S
>


No, in fact the adder is always used with the multiplier. The adder is
actually a tree adder that combines the multiplier partial products and
an additional term from the C input. It is still used to combine
multiplier partial products even if you don't use the C input (not using
it forces a 0 into that input of the adder tree.
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