Inputs and output from ASIC synthesis flow

6.2. Inputs and output from ASIC synthesis flow

Outcome of Synthesis is Gate level netlist which is again in Standard Verilog format. Netlists can be simulated as well which we call as Gate Level Simulation.

6.2.1. Register Transfer Level (RTL) Representation

RTL is the functional specification of the design to logic synthsis which is represented by HDLs.

Ø  Register: Storage element like F-F, latches

Ø  Transfer: Transfer data between input, output and register using combinational logic.

Ø  Level: Level of Abstraction modeled using HDL.

6.2.2. Constraints

The major objective of the logic synthesis is to meet the optimization constraints specified by the designer. Timing, area and power targets are the optimization constraints.

Ø  Timing Constraints: The synthesis tool tries to meet the setup and hold timing constraints on the sequential logic in the design.

Ø  Area constraints: Area constraints specifies maximum area for a design.

Ø  Power Constraints: Power constraints specifies the maximum power consumption for the design.

 

6.2.3. Target Library

 Target library is standard cell library corresponding to a particular technology node (eg. 45nm). This is a collection of combinational logic gates and sequential logic elements which are used to convert HDL to gate level netlist.

 

If logic synthesis is carried ou for FPGAs then HDL description is translated and mapped to LUTs, flip-flops and block RAMs.  For FPGA implementation separate synthesis tool is required. ASIC synthesis tool can’t synthesize the HDL into FPGA omplemtable netlist.

 

A clean technology independent HDL description of design can be synthesized to any technology node. This can also be targeted for FPGA implementations.