Why logic utilization is much higher?

[sli30]

Dear all,

This is my estimated resources on Arria 10. I used Quartus v17.1. The logic utilization is much higher than ALUTs, registers, memory and DSP. Is this normal? Because the other resources are much lower. Why logic utilization is so huge?

+--------------------------------------------------------------------+

; Estimated Resource Usage Summary                                  ;

+----------------------------------------+---------------------------+

; Resource                               + Usage                    ;

+----------------------------------------+---------------------------+

; Logic utilization                      ;  84%                    ;

; ALUTs                                  ;  48%                    ;

; Dedicated logic registers              ;  39%                    ;

; Memory blocks                           ;  34%                    ;

; DSP blocks                             ;  25%                    ;

+----------------------------------------+---------------------------;

[Tricky]

Logic utilisation is a function of your code. So why were you expecting more Mem and DSP usage? have you checked the per-entity logic usage to see if entities where you expected ram are using logic instead? This will usually occur when you have code that cannot infer rams or DSP.

[corestar]

As Tricky said, the logic utilization is not really related to DSP and memory.

If what you are asking is why is the logic utilization so much larger than the ALUT, this link provides some insight:

https://www.intel.com/content/www/us/en/programmable/support/support-resources/knowledge-base/solutions/rd05172012_146.html

(Sorry, new Forums have no way to cleanly insert a link). The key item you may want to pay attention to is "C" which it defines as:

Estimated Combinational ALUT/register/register triples unavailable

In other words, there may be something about your design that is making a large amount of logic unusable.