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Altera_Forum's avatar
Altera_Forum
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8 years ago

lpm functions and hdl

Hi all, So I'm trying to create a (synchronous) 8-bit loadable counter, as below but for some reason this synthesizes to around 28 LE's compared to the altera LPM 11 LE version. Any idea why? ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
8 years ago

Did some more sleuthing and it's indeed the fact that you expose next_q. Without exposing next_q a synchronous, 8-bit loadable counter with asynchronous reset comes in at 9LE's, which is inline with the LPM function.

I'm assuming that counters in lpm functions are just done as flip-flop's rather than adders which expands the whole thing into a 28 bit monster (all things considered). So I now get to choose whether or not I'll take the hit on an extra clock or additional resources :-)

Thanks to all who have replied!

-Mux