SystemC AMS

SystemC AMS is an extension to SystemC for analog, mixed-signal and RF functionality.^[1] The SystemC AMS 2.0 standard was released on April 6, 2016 as IEEE Std 1666.1-2016.

Language specification

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Language features

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MoC - Model of Computation

A model of computation (MoC) is a set of rules defining the behavior and interaction between SystemC AMS primitive modules. SystemC AMS defines the following models of computation: timed data flow (TDF), linear signal flow (LSF) and electrical linear networks (ELN).

TDF - Timed Data Flow

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ELN - Electrical Linear Networks

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LST - Linear Signal Flow

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Ports

TDF in/outport definition:

 sca_tdf::sca_in<PortType>
 sca_tdf::sca_out<PortType>

TDF converter in/outport definition:

 sca_tdf::sc_in<PortType>  // DE → TDF inport
 sca_tdf::sc_out<PortType> // TDF → DE outport

ELN terminal definition:

 sca_eln::sca_terminal

Nodes

 sca_eln::sca_node         // ELN node
 sca_eln::sca_node_ref     // ELN reference node

Cluster

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Tracing

sca_trace_file *tf = sca_create_tabular_trace_file("trace_file_name.dat");
  sca_trace(tf, <PORT|SIGNAL|NODE>, "name");

Example code

TDF

Timed-Data-Flow 1st order low pass model:

#include <systemc-ams>

using namespace sca_util;        // introduced for convenience: sca_util::sca_vector<TYPE> → sca_vector<TYPE>
using namespace sca_core;        // introduced for convenience: sca_core::sca_time() → sca_time()
using namespace sca_ac_analysis; // introduced for convenience: sca_ac_analysis::sca_ac() → sca_ac()

SCA_TDF_MODULE(tdf_low_pass)
{
    // TDF ports
    sca_tdf::sca_in<double>  inp;
    sca_tdf::sca_out<double> outp;

    // parameters
    double fcut;                 // cut-off frequency

    // methods
    void initialize();           // simulator callback for initialization purpose
    void ac_processing();        // simulator callback for AC behavior implementation
    void processing();           // simulator callback for time implementation

    // constructor
    SCA_CTOR(tdf_low_pass) {
    	fcut = 1.0e3;            // cut-off frequency 1kHz
    }

private:
    sca_vector<double > num;	 // numerator coefficients
    sca_vector<double > den;	 // de-numerator coefficients
    sca_vector<double > state;   // state vector
    sca_tdf::sca_ltf_nd ltf_nd;  // linear transfer function (numerator/de-numerator type)
};

linear transfer function:

// initialize linear transfer function coefficients
void tdf_low_pass::initialize(){
  num(0) = 1.0;
  den(0) = 1.0;
  den(1) = 1.0/(2.0*M_PI*fcut);
}

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// AC implementation
void tdf_low_pass::ac_processing(){
  sca_ac(outp) = sca_ac_ltf_nd(num, den, sca_ac(inp));
}

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// time domain implementation
void tdf_low_pass::processing(){
  outp = ltf_nd(num, den, state, inp);
}

ELN

Electrical-Linear-Networks 1st order low pass netlist:

SC_MODULE(eln_low_pass_netlist)
{
    // sca eln terminals
    sca_eln::sca_terminal n1;
    sca_eln::sca_terminal n2;

    // internal nodes
    sca_eln::sca_node_ref gnd;

    // eln modules
    sca_eln::sca_r i_r;
    sca_eln::sca_c i_c;

    SC_CTOR(eln_low_pass_netlist) : i_r("i_r"), i_c("i_c")
    {
          i_r.value = 1.0;
          i_r.p.bind(n1);
          i_r.n.bind(n2);

          i_c.value = 1.0/(2.0*M_PI*1.0e3);
          i_c.p.bind(n2);
          i_c.n.bind(gnd);
    }
};

LSF

Linear-Signal-Flow netlist:

History

SystemC AMS study group was founded in 2002 to develop and maintain analog and mixed-signal extensions to SystemC, and to initiate an OSCI (Open SystemC initiative) SystemC-AMS working group. The study group has made initial investigations and specified and implemented a SystemC extension to demonstrate feasibility of the approach. In 2006, a SystemC AMS working group has been funded which continued the work of the study group inside OSCI, and now goes on to work on SystemC AMS within the Accellera Systems Initiative, resulting in the AMS 1.0 standard in 2010. After the release of the Accellera SystemC AMS 2.0 standard in 2013, the standard was transferred to the IEEE Standards Association in 2014 for further industry adoption and maintenance. The SystemC AMS standard was released April 6, 2016 as IEEE Std 1666.1-2016.^[2][3] COSEDA Technologies provides with COSIDE the first commercially available design environment based on SystemC AMS standard.

• SystemC AMS-Standard IEEE 1666.1-2016
• SystemC AMS Proof-of-Concept Download

References