Skip to main content

Signal Electromigration (Signal EM): Violations, Examples, and Practical Fixes

  Hello Dear Readers,   Today in this post, I will provide some deep insight into the Signal Electromigration (Signal EM): Violations, Examples, and Practical Fixes. 1. Introduction: As technology nodes shrink into the deep‑submicron and nanometer regime (7nm, 5nm, 3nm and beyond), electromigration (EM) has become a first‑order reliability concern—not only for power/ground (PG) networks but also for signal nets. Signal EM failures are often underestimated because signal currents are transient and bidirectional. However, with higher switching activity, tighter metal pitches, thinner wires, and aggressive timing closure, signal EM can cause latent or early‑life failures if not addressed properly. This article explains: What Signal EM is and how it differs from PG EM Typical Signal EM violation scenarios Detailed, practical examples Root causes behind each violation Proven solutions and best practices to fix and prevent Signal EM issues 2. What is Signal Electromigration: El...
Post a Comment

Multiplexer Verilog Code

Hello Dear Readers,

Here I have giving Verilog code of 32-bit Multiplexer which is a common digital system block. A multiplexer selects an input from multiple inputs. The following code implements a 32-bit 2-to-1 multiplexer as well as a 4-to-1 multiplexer using a function. The [31:0] denotes a bus that has 32 bits. So Let's Start it code.

Verilog Code:

1) Multiplexer Using Dataflow Level:

module mux2to1 (a0,a1,s,y); // multiplexer, 32 bits 
 // inputs, 32 bits
input [31:0] a0, a1;    
  // input selection line, 1 bit    
 input s;   
  // output, 32 bits        
output [31:0] y;       
// ternary operator is used so if (s==1) y=a1; else y=a0;    
assign y = s ? a1 : a0;      
endmodule

Now there is also a function facility available in Verilog similar to C language such functions are sections of Verilog code that allow the Digital Designer to write more reusable and maintainable code. Often a function is created when the same operation is done over and over throughout Verilog code. Rather than rewriting code, one can just call the function. This prevents copy and paste errors and allows for more maintainable code: if the behavior of the function changes, it only needs to be updated in one location. One rule about functions is that they cannot have any time delay (# delay, posedge). This is one way in which they differ from tasks. For this reason, functions are used for creating combinational logic. Yes, functions are synthesizable!

Below is a list of rules for functions:

  • Functions can have any number of inputs but only one output (one return value)
  • The order of inputs to a function dictates how it should be wired up when called
  • The return type defaults to one bit unless defined otherwise
  • Functions execute immediately (zero time delay)
  • Functions can call other functions but they cannot call tasks
  • Functions can drive global variables external to the function
  • Variables declared inside a function are local to that function
  • Non-blocking assignment in function is illegal
  • Functions can be automatic 
The following code implements a 32-bit 4-to-1 multiplexer. A 4-to-1 multiplexer selects one input from four inputs and needs a 2-bit selection signal. The assign statement can also be put in above the function block or the below as shown in the below,

2) Multiplexer Using Function:

module mux4to1 (a0,a1,a2,a3,s,y); // 4-to-1 multiplexer, 32-bit
input [31:0] a0, a1, a2, a3; // inputs, 32 bits 
input [1:0] s; // input, 2 bits 
output [31:0] y; // output, 32 bits 
function [31:0] select; // function name (= return value, 32 bits) 
            input [31:0] a0,a1,a2,a3; // notice the order of the input arguments
            input [1:0] s; // notice the order of the input arguments 
            case (s) // cases:
                 2’b00: select = a0; // if (s==0) return value = a0
                 2’b01: select = a1; // if (s==1) return value = a1
                 2’b10: select = a2; // if (s==2) return value = a2 
                 2’b11: select = a3; // if (s==3) return value = a3
            endcase 
endfunction 
assign y = select(a0,a1,a2,a3,s); // call the function with parameters 
endmodule

Thanks For Reading if any doubts write them in the comments I will be giving a reply asap.

Labels:

Comments

Post a Comment

Popular posts from this blog

Exploring the Role of LEF Files in VLSI Chip Design: A Beginner's Guide

Hello Dear Readers,   Today in this post, I will provide some deep insight into the LEF file role during the VLSI Chip Design process. In VLSI (Very Large Scale Integration) design, a LEF file is a file that contains information about the physical geometry of the standard cells used in a circuit. LEF stands for Library Exchange Format. A standard cell is a pre-designed logic cell that contains a specific function, such as a flip-flop or an AND gate. Standard cells are designed to be easily combinable and scalable to create more complex circuits. The physical geometry of each standard cell is defined in the LEF file. The LEF file contains information such as the width, height, and position of the pins and metal layers of each standard cell. It also contains information about the physical design rules that govern the placement of these cells on the chip. LEF files are important in VLSI design because they enable the interoperability of different design tools from different vend...
4 comments
Read more

Best Book for Designing Microarchitecture of Microprocessor Using Verilog HDL

  Hello Dear Readers, Currently, after succeeding in many topics now I starting to provide technical book reviews which were I have completed and still read books always. So let us start today's book review. Book Name:   Computer Principles and Design in Verilog  HDL Description:  Uses Verilog HDL to illustrate computer architecture and microprocessor design, allowing readers to readily simulate and adjust the operation of each design, and thus build industrially relevant skills Introduces the computer principles, computer design, and how to use Verilog HDL (Hardware Description Language) to implement the design Provides the skills for designing processor/arithmetic/cpu chips, including the unique application of Verilog HDL material for CPU (central processing unit) implementation Despite the many books on Verilog and computer architecture and microprocessor design, few, if any, use Verilog as a key tool in helping a student to understand these design techniques...
3 comments
Read more

RTL Design Engineer at Skyroot Aerospace

Hello, Dear Readers, Skyroot Aerospace has a vacancy for the RTL Design Engineer role. About Skyroot Aerospace: A cutting-edge startup founded by ex-ISRO scientists. Dedicated to affordable space access, we're rewriting aerospace technology rules. Our dynamic team fosters inventiveness, collaboration, and relentless excellence. Join us on a transformative journey to redefine space possibilities. Welcome to the forefront of space innovation with Skyroot Aerospace! Purpose of role: Understand architectural requirements and Design micro-architecture, implement design blocks using VHDL/Verilog for FPGA based Avionics packages for orbital launch vehicles and ground infrastructure. Job Requirements: 2+ Years of RTL and system design experience. Strong knowledge on Digital System Design (DSD). Strong knowledge of RTL/SoC design/integration with VHDL/Verilog. Strong knowledge in problem solving and debugging skills. Ability to understand architectural requirements and Design micro-archite...
Post a Comment
Read more