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Martin Barnasconi

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Martin Barnasconi last won the day on March 12

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  1. Your approach to connect he SystemC/TLM world with the SystemC-AMS is correct: to cross the discrete-event / TDF MoC boundary, dedicated converter ports are available for this, called sca_tdf::sca_de::sca_in/out, as explained in section 2.4 of the SystemC-AMS user's guide. Special attention is required to understand when digital discrete-event samples are (made) available in the TDF context. In the case of fixed TDF timesteps, a signal change at an input port of type sca_tdf::sca_de::sca_in is not immediately picked-up by the TDF model, since it runs on its own time step (set by set_timestep), which means the value will be used at the next TDF time step. In case you expect immediate action in the TDF model, then you need to make use of the dynamic timestep feature in SystemC-AMS, by using the SystemC-AMS TDF method request_next_activation in a change_attributes callback. This is explained in section 2.4.3. Note that when using dynamic timestep in a TDF module, you need to make sure other TDF modules in the same TDF cluster support dynamic timesteps, as explained in section 2.1.2. This means all other connected modules should "opt-in" to indicate that they support dynamic timesteps by explicitly calling the method accept_attribute_changes.
  2. It is recommended not to use VCD trace files for TDF, LSF and ELN signals due to their continuous-time nature. Instead you should use the tabular tracefile format. You can open that it many tools since it is basically a ASCII based file with space-separated columns.
  3. You need to specify the timestep to at least one TDF module or TDF port, using method set_timestep. In a TDF module this method should be called in the callback set_attributes. See section 2.3.1 (Discrete-time modeling) and Example 2.11 in the SystemC-AMS User's Guide.
  4. statistics_config is not part of the SystemC AMS language standard (IEEE 1666.1-2016) and as such also not described in the users guide.
  5. The behavior your describe is correct and caused by the discrete-event behavior of the SystemC kernel. I suggest to read section 2.4.1 (Reading from the discrete-event domain) in the SystemC AMS user guide.
  6. There is no such thing as a default state. Equation 7.34 in the 1666.1-2016 LRM defines the contribution of the switch to the equation system, and depends on the value of the control signal (ctrl) of the switch. Since the type of the control signal should be a Boolean value, the initial value can be true or false, which is driven from the digital discrete-event side.
  7. Yes, many publications have been posted on this during the last decade. Check IEEEEXplore for the papers. Another approach is check publications from DOCEA POWER, a company which was focusing on this, and is still active in this domain (although under a different name)
  8. Accellera released the SystemC AMS user's guide application examples, which are available for download via this link. These examples can be executed using your preferred EDA tools, as long as they support the SystemC and SystemC AMS language standard. Alternatively, you can use the open source SystemC and SystemC AMS reference implementations. Instructions for installation and execution can be found in the INSTALL or README files as part of these packages. We welcome your feedback!
  9. The SystemC AMS standard defines in section 9.1.2.6 (sca_util::sca_trace) that it can trace objects of type sca_traceable_object. Since all ELN primitives are derived of this type, you can simply trace the ELN component itself, see example below SC_MODULE(eln_circuit) { // node declaration sca_eln::sca_node n1; // ELN node sca_eln::sca_node_ref gnd; // ELN ground // component declaration sca_eln::sca_vsource vin; sca_eln::sca_r r1; // constructor including ELN netlist eln_circuit( sc_core::sc_module_name nm ) : vin("vin", 0.0, 1.23), r1("r1", 1e3) { // Only ELN primitives requires explicit timestep assignment to one element vin.set_timestep(1.0, sc_core::SC_MS); // netlist vin.p(n1); vin.n(gnd); r1.p(n1); r1.n(gnd); } }; int sc_main(int argc, char* argv[]) { eln_circuit cir("eln_circuit"); sca_util::sca_trace_file* tf = sca_util::sca_create_tabular_trace_file("trace.dat"); sca_util::sca_trace(tf, cir.n1, "v_n1"); sca_util::sca_trace(tf, cir.vin, "i_through_vin"); sca_util::sca_trace(tf, cir.r1, "i_through_r1"); sc_core::sc_start(1.0, sc_core::SC_MS); sca_util::sca_close_tabular_trace_file(tf); return 0; }
  10. The 2020 edition of the SystemC AMS user's guide is available here https://www.accellera.org/downloads/standards/systemc
  11. The Accellera SystemC AMS Working Group released the 2020 edition of the SystemC AMS User's Guide. You will find the user's guide on this page: https://www.accellera.org/downloads/standards/systemc This version of the user's guide is fully compatible with the SystemC AMS standard released as IEEE Std. 1666.1-2016. It describes all the features introduced in the SystemC AMS language standard during the last decade. For example, the user’s guide now explains the use of the dynamic timed data flow capabilities, to make AMS system simulations even more efficient and running even faster. The SystemC AMS Working Group is currently preparing the release of the user's guide application examples as separate download. Availability of these application examples will be communicated at a later stage. Please use this forum to post your questions or remarks on the user's guide.
  12. The code snippet listed above shows that the file is repeatedly opened in the processing() method, since this method is called at each time step. Instead, the file should only be opened once, e.g. in the module constructor or initialize() callback. Note that in this case you need to make the variable of type ifstream a (private) member of the class, so other methods can access this variable.
  13. Indeed, the Accellera SystemC AMS working group is currently active in updating the SystemC AMS user's guide, including an detailed explanation of the dynamic TDF features introduced since SystemC AMS 2.0 (and also incorporated in the IEEE 1666.1 standard) and obviously removing deprecated methods. Examples have been presented in various workshops and tutorials given the last decade at DATE, DVCon Europe, DAC conferences. Please check the SystemC AMS community pages for some of the links. https://accellera.org/community/systemc/about-systemc-ams The "golden reference" for SystemC AMS documentation is actually the IEEE 1666.1 standard itself. Although it might require some practice to understand all the formal definitins and terms, it well explains the underlying concept and the modeling capabilities of the language. The standard can be found here, and thanks to Accellera you can download a copy via the IEEE Get Program here: https://standards.ieee.org/standard/1666_1-2016.html It is well known that SystemC AMS is much faster than Simulink. Actually I consider your 20x speed improvement rather modest, probably since your design is relatively small (this also holds for most of the academic papers I've seen). My observation is that bigger systems in SystemC-AMS show an even bigger speed difference in favor of SystemC-AMS.
  14. The (old) SystemC AMS User's Guide is now directly accessible via this link: http://www.accellera.org/images/downloads/standards/systemc/OSCI_SystemC_AMS_Users_Guide.pdf And also listed in the overview of SystemC standards: http://www.accellera.org/downloads/standards/systemc As mentioned before, the AMS Working Group members are currently working on the update of the User's Guide by including the dynamic TDF timestep features which are also part of the IEEE 1666.1 standard.
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