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Mixed Analog/Digital Simulation (Verilog-AMS)

Analogue and Mixed simulation is not examinable in 16/17.

Hybrid System simulations: typically a digital (embedded) controller interacts with analogue plant.

Example: Vehicle hybrid power system and automatic braking system.

We need to be able to combine digital (event-driven) simulation with analogue models, such as fluid-flow nodal analysis and FDTD modelling.

Cyberphysical tends: »Cyberphysical Functional Mock Up Interface

Relevant tools: Verilog-AMS, VHDL-AMS, Modelica, Simulink and FMI. »Wikipedia: Verilog-AMS

Verilog Analogue and Mixed Signal (AMS) extends RTL to support:

Examples:

// Three 1.5 cells in series make a 4.5 volt battery.
module Battery4V5(input voltage anode, output voltage cathode);
  voltage t1, t2;
  analog begin 
    V(anode) <+ 1.5 + V(t2);
    V(t2) <+ 1.5 + V(t1);
    V(t2) <+ 1.5 + V(cathode);
  end
endmodule
module resistor (inout electrical a, inout electrical b);
  parameter real R = 4700;
  analog V(a,b) <+ R * I(a,b);
endmodule

Verilog simulation cycle extended to support solving nodal flow equations.

When we potentially de-queue a time-advancing event from EDS queue we first roll forward the FDTD simulations which themselves may contain `cross' and similar sensitivity that insert new events on the EDS queue.


39: (C) 2008-17, DJ Greaves, University of Cambridge, Computer Laboratory.   TAPE MISSING ICON