Q1: Let's say that I had created 16 input XOR, 16XOR, and I
assign it with simulation function of 2XOR. Now will the function of the component be as
the XOR one?
Inorder to simulate a 16 XOR with 2XOR, you will have to write the truth table and create
a circuit that produces the same functionality as 16XOR using 2XORs (or any other
simulated gates). In EDSpice you can attach this subcircuit to 16XOR. In this case when
you run simulation, the Simulator will take the simulation results of the subcircuit
attached to 16XOR. However attaching subcircuits is not possible in Mixed Mode Simulator.
In Mixed Mode, you will have to replace 16XOR with the corresponding reduced circuit and
then run the simulation.
Q2: Provision is made only for entering the text in the
'Schematic Editor' and if I enter the component values as text then they do not change
when I change the value of the component during simulation.
The value may be given to the component using Add/ Change Text tool along with the option,
Add/ Change value enabled. This value is accepted by Simulator. But after every change is
made, remember to run Preprocess in Mixed Mode Simulator window to make the changes
active.
Q3: I can't simulate a Logic Component like Operational
Amplifier or Multiplier (AD632). In fact, when I go to Mixed Mode Simulation, EDWin says
that it's a not simulated component. But in Database filter, there is no problem. Do you
have an answer?
To know whether a component can be simulated or not, open Library Browser. From View/
Options menu, check the option ‘Simulation Function’ and search for the
component. If the component is having a simulation function, the information will be
listed in the table corresponding to ‘Simulation Function’ below after the
search.
AD632 does not have simulation functions assigned to it. The only OPAMP that has
simulation primitives assigned to it in mixed mode is OPAMPA in the library file
a_linop.SYMBOL. The same simulation primitives may be assigned to any other opamp that has
matching number of pins
Q4: How can LED’s and 7 segment displays be simulated?
You can assign the simulation function for Diode to LED symbol and do the simulation in
Mixed Mode Simulator. In EDSpice, there are Model parameters for LED's in LED.sparam.
Q5: What is written in clock generator string to output 15 KHz
clock pulses? How can 15KHz clock pulses be detected?
(H20,L47)[?s] as generator string, will produce a Pulse train, starting with a Mark of 20
micro seconds and a Space of 47 micro seconds, the time period is 67 micro seconds (for
15Khz, it is 66.67 micro seconds, To increase the precision, choose time in nano seconds,
ns instead of ?s, and give appropriate values). For a pulse Train of 100, the generator
string is 100(H20,L47)[?s]. Add ‘Logic state TP’ right at the pin where you
assigned the Generator String and when Transient analysis is done, you get the Pulse
Waveform in the diagram.
Q6: Can custom Mixed-Mode simulator models be created?
Yes, custom mixed mode simulator models may be created provided simulation primitives are
available. If the symbol works like any other symbol for which a simulation primitive is
already available, you can assign the same primitive to it. If not, you will have to write
the DLL (simulation primitives) for simulating it and then assign it. The DLL primitive
source code is written in C programming language. The creation or updation of the
primitives requires some knowledge and practice with the C programming language. You may
find the necessary documents for this on the EDWin XP/2000 CD under the directory named
Simmodel.kit.
Q7: I'm trying to add a new component to Edwin and have some
questions. When creating a new Part, you can assign a simulation function to it. But I
can't find the way of specifying it's electrical characteristics and save them within the
Part. Where can I enter these parameters?
You can assign simulation function to a symbol. After assigning the simulation function to
the symbol, load it into the project. Invoke Mixed mode Simulator and select the tool
"Set parameter" (option tool of the functional tool “Set parameter/
Models”) in the tool bar and click on the symbol. You will get a window where you can
edit/ enter the values. Save the edited parameters into a separate library.
Q8: Making changes to schematic circuit and preprocessing does
not appear to re-configure the 'nets' correctly i.e., have to re-edit the nets?
Always see that you edit the net and not the wire connection. For example if you delete a
wire in schematic, the wire gets deleted but the net remains. So after preprocessing, the
net still remains. Before making any changes to nets you should confirm that you deleted
the net or a part of it. Deleting wire connection will not delete net connection. It only
deletes physical representation.
Q9: I am trying to use the mixed mode simulator to calculate
power on a resistor. In the waveform viewer, I click ADD to add a trace, then type in a
formula PWR (R9) that generates an error when I try to APPLY it. The plot shows zero
power. How do you get a plot of the power in a resistor?
To calculate the power in a resistor, you should place two markers for voltage and current
at the resistor node and from the equation generator, explicitly enter the variables in
the format Voltage* Current and then calculate the power.
For e.g.: enter in the expression list box:
V1 (GEN) * I1 (Unpck16: PIN1)
to calculate the power at a resistor. And in the Units list box enter the unit to which
the diagram should be displayed, i.e. W.
The PWR function is unused for calculate the X raised to the power of Y.
For e.g.: PWR (3,2) which will give you 9 as output.
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