Logic Simulation 한양대학교 신현철 교수

CAD and Design Project Course for SoC Circuit Simulation (1/2) Real-delay Simulation (Using HSPICE)

CAD and Design Project Course for SoC Circuit Simulation (2/2) Zero-delay Simulation (Using ModelSim)

CAD and Design Project Course for SoC Logic Simulation (1/3) Digital Logic Circuit Diagram Boolean Function  Y = (A&B) | (!(B&C)&D)  Z = (!(B&C)&D) | (!(B&C)&E)

CAD and Design Project Course for SoC Given the boolean function of a net, you can calculate the logic value. If the circuit size is doubled, the cost for logic simulation will be quadrapled.  Recently, the number of CPU gates is over one million. Ex) Pentium 4 chipset, Altera FPGA, … Logic Simulation (2/3)

CAD and Design Project Course for SoC If the boolean function is simplified, logic simulation time becomes shorter.  Simplification of boolean function using BDD  Simplification of boolean function using Espresso tool  Simplification of boolean function using SIS tool But, if the input vector is changed, all logic values of the nets have to be recalculated.  Simulation cost is still high. If only changed values are calculated, simulation time can be shorter. Logic Simulation (3/3)

CAD and Design Project Course for SoC Circuit Data Structure (1/3) Input Pattern (ISCAS’85 C17 benchmark circuit) outputgate typeinput ** Gate type ** Inverter : 2 AND gate : 3 OR gate: 4 NAND gate : 5 NOR gate: 6 XOR gate: 7 XNOR gate : 8 INPUT PIN : 0 OUTPUT PIN : 1

CAD and Design Project Course for SoC Circuit Data Structure (2/3) Build Graph

CAD and Design Project Course for SoC Circuit Data Structure (3/3) Vertex Structure

CAD and Design Project Course for SoC Level Decision Algorithm Pseudo code

CAD and Design Project Course for SoC Level Decision Algorithm Initialize level to 0 and schedule primary inputs

CAD and Design Project Course for SoC Level Decision Algorithm Decide level

CAD and Design Project Course for SoC Logic Calculation Algorithm Pseudo code

CAD and Design Project Course for SoC Logic Calculation Algorithm (1/3) Initialize all logic values

CAD and Design Project Course for SoC Logic Calculation Algorithm (2/3) Calculate logic value

CAD and Design Project Course for SoC 16 Logic Calculation Algorithm (3/3) Calculate switching count Level 0 : 3 Level 1 : 2 Level 2 : 1 Level 3 : 1

CAD and Design Project Course for SoC Result Format