1. Modeling and the simulator of Digital Circuits in Object-Oriented Programming Stefan Senczyna Department of Fundamentals of Technical Systems The Silesian University of Technology

2. 1. Digital system a digital system is an image of connected elements and modules of hardware, logical functions, a schema, a hardware description gives ‘an image of hardware’, which regard formal, structural, behavioral aspects of digital systems, the definition of VHDL is consequently extended, what makes the VHDL as an reference for HDL’s.

3. 2. Object modeling of digital systems 2.1 Mapping of a digital system structure assuming, a digital system is a structure of connected modules, the structure can map an object model, using object-modeling technique, the base of an object model is hierarchy of classes, hierarchy of classes defines semantics of the object model,

4. 2.1 Mapping of a digital system structure assuming, the model of a digital system contains objects, which are derived from a class ‘digital system’, then an example of hierarchy of classes presents the diagram: System Module B Connection Module A in object modeling of digital systems every case of a digital system has a structure, an equivalent classes hierarchy maps the structure,

5. 2.3 Goals of object modeling the mapping of digital system structure and properties, the simulator of a digital system, using assumptions: –an object model of the digital system is an instance of reactive automaton, –behavior of the digital system defines a sequences of inputs and outputs transactions, –a transition function of the automaton is the ‘delay’, –the definition of semantics of the simulator.

6. 3. Creating an object model for digital system 3.1 Assumptions to the model a digital system is an image of hardware, divided to layers: –data flows between modules, –register transfer data, –logical signals flows, the object model is an equivalent of the VHDL description in sense of reactive automaton.

7. 3.2 An object model of the digital system layers of digital system are classes, connections, elements, modules are objects, physical properties of hardware map properties of objects an example of the model presents the diagram: System AB Module A Module B Connection A-B Connection

8. 3.2 An object model of the digital system the digital system model is created in object-oriented programming digitalsystem Module_A namespace simulator { public class digitalsystem { public module_A m1; public digitalsystem () { m1 = new module_A (); } public class module_1 { public module_A () { }

9. 3.3 The simulator of the digital system assumptions: –the object model is constrained to the layer of logical signals flows, –a layer of logical signals flows contains of modules and connections, –an object model is built from objects of the module type and the connection type, –each object of type ‘module’ includes a method ‘simulator’, regarding the ‘system’ is a type ‘module’, –each method of the simulator implements an event- driven algorithm

10. 3.3 The simulator of the digital system System AB Module AModule B Connection AB Connection Simulator B Simulator A Simulator AB

11. 3.3 The simulator of the digital system an implementation: –the implementation is decomposed to a set of methods, –the method ‘simulator AB’ include the method ‘simulator A, and the method ‘simulator A’, –a formula: ‘if simulator A and simulator B then simulator A-B’ defines the decomposition Simulator A Simulator B Simulator AB

12. 4. Components generator the decomposition is created for the object model of a digital system, a set of rules produces a decomposition, a set of rules is a components generator.