... how to find now the p and g?
It's all described in the Weste/Harris book, s. here: View attachment 61439 .
You should run the same simulation analyses corresponding to Fig. 5.28 for fanOut 1..n (1..8 in Fig 5.28 (b) , maybe n=4 or 5 should be enough) ...
- for your AND2
- for the smallest INV
- from their slopes ratio you'll get g
- then do the same without any load after your DUT (i.e. without the X4, X5 gates)
- then from their (AND2/INV slopes) ratio you'll get p
Of course you need the 'measure' statements. tpd is what you need for the ordinate dabs in FIG 5.28 (b) .is this code correct for logical effort?
Or i have to add new code?
As I told you above. Read thoroughly!And finally how i will find the slopes that you describe above?
Is soething wrong with the code? Or the topology of the circuit?
the truth is that hspice is not familiar to me..but i try it..the problem is that i havent plenty of time to learn all the hspice manual.I really wonder if you know what you're doing?
Circuit topology is ok (for fanOut=1). But for propagation delay measurement (tpd.) of a non-inverting gate (your AND2) you have to measure the tpdr from rise to rise and tpdf from fall to fall.
You don't need to learn all the hspice manual. But you should essentially know what you want to measure!the truth is that hspice is not familiar to me..but i try it..the problem is that i havent plenty of time to learn all the hspice manual.
Did you measure from rise=1 to rise=2 , and from fall=1 to fall=2 ?I tried this but again tpdf= failed and targ= not found therefore tpd failed.
Of course, because the measurement statements had been created for an (inverting) NAND gate!I tried with inverter and NAND2 and i got tpdf tpdr and tpd without any problem.
This is a non-inverting gate, so you have to measure propagation delay times from first rise to second rise, resp. from first fall to second fall:whats going on with AND2?
.measure tpdr
+ trig v(c1) val='supply/2' rise=1
+ targ v(d1) val='supply/2' rise=2
.measure tpdf
+ trig v(c1) val='supply/2' fall=1
+ targ v(d1) val='supply/2' fall=2
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