27 October

Module Constraint Types : Guide, Fence and Region

Sometimes we need to place a particular group of standard cells or modules in a particular area (box). PnR tools allow us to do that. If I talk particularly about Cadence Innovus APR tool, It has three types of regions called Guide, Fence and Region through which we can provide guidance to the placement tool. Let's explore what actually these three placement constraints do and what are the differences.



  • The guide is assigned with certain cells in the design
  • The guide allows to assigned cell sit outside the box
  • It also allows the other cells to sit inside the box
  • It is a soft constraint.

Innovus command:

createGuide obj_name box


createGuide adder9 100.000 200.000 110.000 210.000

This is will create a guide for the module adder9 to the box (100 200 110 210)


  • The fence is assigned with certain cells in the design.
  • A fence does not allow the assigned cell to sit outside the box defined.
  • A fence does not allow the other cells to sit inside the box also. So the area is exclusively reserved for the assigned cells.
  • It is a hard constraint

Innovus command:

createFence obj_name box


createFence SH12 200 400 220 440

This is will create a fence for the module SH12 to the box (200 400 220 440)


  • The region is assigned with certain cells in the design.
  • A region does not allow the assigned cell to sit outside the box defined.
  • It may cause congestion in the area assigned if not chosen the area wisely.
  • The only difference between the region and fence is that it allows the other cells to sit inside the box. 
  • It is a hard constraint

Innovus command:

createRegion obj_name box


createRegion SH7 200 400 220 440

This is will create a module guide in floorplan view with the status region for SH7 module to the box (200 400 220 440)

Delete module guide :

  • The delete the Guide / Fence / Region for the module use unplaceGuide command.


unplaceGuide SH7 

This will delete the module guide for the SH7 module

13 October

Best 25 books on VLSI Design

In the previous article, Best 5 books have recommended for Physical Design Engineer. While writing that article it was very difficult to make many books out of the list. So I thought it will be better to write another article on the best 25 books for VLSI Design. This list starts from the basic level of books to the advance level of books. I have categories these books into 8 major categories. 

If you wish you buy any books, I have searched the bestseller, best edition and best price of these books and linked here. You can buy these books from these links through amazon. 

I. Basic Digital Electronics

1. Electronic Devices And Circuits Theory by Robert L. Boylestad 

The main content of this book is as follow:

  1. Semiconductor Diodes
  2. Diode applications
  3. Bipolar Junction Transistor
  4. DC Biasing - BJT
  5. BJT AC Analysis
  6. Field-Effect Transistors
  7. FET Biasing 
  8. FET amplifier
  9. BJT and JFET Frequency response
  10. Operational Amplifiers
  11. OP-Amp applications 
  12. Power Amplifiers
  13. Linear Digital ICs
  14. Feedback and Oscillator Circuits
  15. Power Supply (Voltage Regulators)
  16. Other Two Terminals Devices
  17. PNPN and other devices

2. Digital Design with an Introduction to the Verilog HDL by M. Morris Mano 

The main content of this book is as follow:
  1. Binary Systems
  2. Boolean Algebra and Logic Gates
  3. Simplification of Boolean Functions
  4. Combinational Logic
  5. MSI and PLD Components
  6. Synchronous Sequential Logic
  7. Registers, Counters and The Memory Units
  8. Algorithm State Machines (ASM)
  9. Asynchronous Sequential Logic
  10. Digital Integrated Circuits
  11. Laboratory Experiments
  12. Standard Graphics Symbols

II. Verilog HDL and SystemVerilog

3. Verilog HDL by Samir Palnitkar 

The main content of this book is as follow:

1 Overview of Digital Design with Verilog HDL 
2 Hierarchical Modeling Concepts 
3 Basic Concepts 
4 Modules and Ports 
5 Gate-Level Modeling 
6 Dataflow Modeling 
7 Behavioral Modeling 
8 Tasks and Functions 
9 Useful Modeling Techniques 
10 Timing and Delays 
11 Switch-Level Modeling 
12 User-Defined Primitives 
13 Programming Language Interface 
14 Logic Synthesis with Verilog HDL

4. FPGA Prototyping by Verilog Examples by Pong P. Chu 

The main content of this book is as follow:
  1. Gate-Level Combinational Circuits
  2. Overview of FPGA and EDA software
  3. RTL combinational circuit
  4. Regular Sequential Circuit
  5. FSM
  6. FSMD
  7. Selected Topics of Verilog
  8. UART
  9. PS2 Keyboard
  10. PS2 Mouse
  11. External SRAM
  12. Xilinx Spartan-3 Specific Memory
  13. VGA Controller -1: Graphics
  14. VGA Controller-II: Text
  15. PicoBlaze Overview
  16. PicoBlaze Assembly Code Development
  17. PicoBlaze I/O Interface
  18. PicoBlaze Interrupt Interface
  19. Simple Verilog Templates

5. SystemVerilog for Verification by Chris Spear 

The main content of this book is as follow:
  1. Verification Guidelines
  2. Data Types Procedural Statements and Routines
  3. Connecting the Testbench and Design
  4. Basic OOP
  5. Randomization Threads and Interprocess Communication
  6. Advanced OOP and Testbench Guidelines
  7. Functional Coverage
  8. Advanced Interfaces
  9. A Complete SystemVerilog Testbench
  10. Interfacing with C/C++

III. Semiconductor Devices

6. Solid State Electronic Devices by Streetman and Banerjee

7. VLSI Technology by S. M. SZE

8. The MOS Transistor by Yanish Tsividis

IV. Fabrication Technologies

9. The Science and Engineering of Microelectronic Fabrication by Stephen A Campbell 

9.a. Fundamental of Semiconductor Fabrication by S M SZE

The main content of this book is as follow:

  1. Introduction
  2. Crystal Growth
  3. Silicon Oxidation
  4. Photolithography
  5. Etching
  6. Diffusion
  7. Ion Implantation
  8. Film Deposition
  9. Process Integration
  10. IC Manufacturing
  11. Future Trends and Challenges

V. Analog Design

10. Design of Analog CMOS Integrated Circuits by Behzad Razavi

11. Microelectronic Circuit Theory and Application by Sedra and Smith

12. CMOS Circuit Design, Layout and Simulation by R. Jacob Baker

VI. Digital Design

13. CMOS Digital Integrated Circuit by Sung-Mo Kang and Yusuf Leblebici

14. Digital Integrated Circuit by Rabaey

15. CMOS VLSI Design by Neil H E Weste 

VII. Low Power Design

16. Low Power CMOS VLSI Circuit Design by Kaushik Roy 

17. Practical Low Power VLSI Design by Gary K. Yeap

VIII. Advance Books

18. Static Timing Analysis For Nanometer Design by J Bhaskar 

The main content of this book is as follow:

    1. CHAPTER 1: Introduction
    2. CHAPTER 2: STA Concepts
    3. CHAPTER 3: Standard Cell Library
    4. CHAPTER 4: Interconnect Parasitics
    5. CHAPTER 5: Delay Calculation
    6. CHAPTER 6: Crosstalk and Noise
    7. CHAPTER 7: Configuring the STA Environment
    8. CHAPTER 8: Timing Verification
    9. CHAPTER 9: Interface Analysis
    10. CHAPTER 10: Robust Verification

19. Constraining Design for Synthesis and Timing Analysis by Sridhar Gangadharan  


20. Advance ASIC Chip Synthesis by Himanshu Bhatnagar 

The main content of this book is as follow:


21. Physical Design Essentials by Khosrow Golshan

The main content of this book is as follow:

Chapter 1: Libraries 
1.1 Standard Cells 1.4 Library Characterization
Chapter 2: Floorplanning
2.1 Technology File 2.3 Design Constraints
2.4 Design Planning
2.5 Pad Placement
2.6 Power Planning
2.7 Macro Placement
Chapter 3: Placement 
3.1 Global Placement 3.2 Detail Placement
3.3 Clock Tree Synthesis
3.4 Power Analysis
Chapter 4: Routing 
4.1 Special Routing
4.2 Global Routing
4.3 Detail Routing
4.4 Extraction
Chapter 5: Verification
5.1 Functional Verification 5.2 Timing Verification
5.3 Physical Verification
Chapter 6: Testing
6.1 Functional Test
6.2 Scan Test 6.3 Boundary Scan Test
6.4 Fault Detection
6.5 Parametric Test
6.8 Memory Test

22. Algorithm for VLSI Physical Design Automation by Naveed Sherwani

23. VLSI Design Methodology Development by Thomas Dillinger

24. Characterization and Modeling of Digital Circuits by Rohit Sharma

25. The Art of Timing Closure by Khosrow Golshan


Hope this article will help you to decide which are the best books available and which you need to read. 

Thank you!