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Circuit Development with microcontrollers, simulation in pspice

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Last Modified: 2008-07-15
Hello,

After spending an extensive amount of time researching online the last three days I've come to the conclusion you cannot create a complete circuit, inside OrCad Capture with PSpice models and attempt to simulate it if the circuit contains a microcontroller.  I was hopeful matlab simulink would somehow solve this problem (I was hoping the c code could somehow be ran in that program in block connected to orcad), however, my research has determined you can only download the code into a real, physical microcontroller and run it that way.

Since this is the case, I would like to ask a few experts how one would go about using orcad tools to design such a system.  For example, presume for a second I have a full circuit which contains analog input circuitry, some FPGAs / AtoDs (or other devices which can be simulated in PSpice), and all of this centers around a microcontroller or processor.  How do I design such a system, today, in the real world?

It appears I would have to break up my circuit into the pieces that are simulatable, and the pieces which are invariable tied to the microcontroller.  

I apologize if this question seems a little vague or open ended, but as I gain more experience into real electrical design (which I am in my third month of doing for a real job) these are the kinds of questions I'm running into.

Stepping back and thinking about the big picture, in order to just include a microcontroller into a design (or processor) I would need to look at the datasheet / user manual and first discover what the input / output impedance of each pin would be.  The speed of each pin would also be important, not only for the electronics connecting to the device but also for the board layout (of which I'm also gaining experience doing).  Besides ensuring signal integrity (such as providing pull up / down resistors, protecting against high currents) I can't think of what else I need to care about when designing a microcontroller into a board.

That said, I suppose I have two questions here:  In what ways can I involve microprocessors / microcontrollers in a simulated design, specifically orcad pspice (because that's the tool I have access too), and what other characteristics should I be concerned about for these designs.

I apologize for the length of this question but also sincerely appreciate any responses which may show up.
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