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I have this in an exercise and it asks me to find the frequency of the CPU. I know how to calculate it for smaller drawings, but how many times does every I-Mem, Add, MUX, ALU, Regs, D-Mem and Control run?

*I Calculated at about 740MHz but the solution is 783, so this is why i'm asking you.

I-Mem = 412ps
Add  =  120ps
MUX  =  21ps
ALU  =  120ps
Regs =  197ps
D-Mem = 351ps
Control=115ps
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  • \$\begingroup\$ I think we need chip timings? \$\endgroup\$ – MadHatter Jun 8 '17 at 17:04
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    \$\begingroup\$ You have to find the critical path for all your implemented instructions, the biggest one will give you the maximum frequency \$\endgroup\$ – Don Jun 8 '17 at 20:03
  • \$\begingroup\$ As a first guess the instruction lw (load word) has a high propagation delay \$\endgroup\$ – Don Jun 8 '17 at 20:07
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    \$\begingroup\$ Questions on Stack Exchange sites are resolved by posting and accepting an answer (even if it is your own), not by editing the question. Your improper edit has been reverted - post your solution as an answer. \$\endgroup\$ – Chris Stratton Jun 9 '17 at 15:55
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So the correct solution is:

Time=Imem+Dmem+ALU+2*Reg

&

f=1000/Time

(Which is 0.783 GHz in this case)

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