Digital Systems Design Tutorials

The digital systems are spread to a wide range of applications including computer, mobile phones, control systems.

Digital system deals with different types of elements such as hardware, software, network and their applications. If you combine these elements together and forms a system is called as digital system design. There are many different components that designs a system

Overview of Digital Systems Design -VLSI Basics

Let’s go through the overview, then we will get to know more about basics of VLSI designs.

Importance of Digital Systems Design:

Digital Systems Design is economical and easy to program. It is easy to duplicate similar circuits and complex digital ICs using microelectronics Technology. Digital System Designs in Embedded system can able to reduce the size and cost of the product. Data is represented in a digital system as a vector of binary variables. They can provide accuracy and runs with less noise. Digital systems are less prone to error than analog systems. Data representation in a digital system is suitable for error detection and correction. Digital electronics is a field of electronics involving the study of digital signals and to produce devices. Digital electronic circuits are usually made from large assemblies of logic gates, often packaged in integrated circuits

What is VLSI?

VLSI is the abbreviation of Very large-scale integration. It is the process of creating single chip by using Integrated Circuit

In 1970, When MOS integrated circuit chips were widely used to enable complex semiconductor and electronic devices, then VLSI technology started its footprint.

The knowledge of digital electronics, along with strong base knowledge in either VHDL or Verilog HDL are so important.

 Finite State Machine and First in First Out (FIFO) are the techniques used in the logic design of VLSI circuits.

VLSI devices are microprocessors and microchips, they can perform more complex functions.

The main advantages of VLSI technology are easiness to IC designers to add major components like CPU, ROM, RAM, etc. into one chip

Brief Overview about VLSI:

VLSI term originated according to number of transistors or gates used into a chip.

VLSI chips are used in mobile phones, cars, medical devices and many other places. Before VLSI, most ICs had limited functions.

As technologies grows fast, there is a constant need to design, develop integrated circuits.

Since products like mobile phones are released with new features very often, VLSI technology is still in high demand.

With the help of VLSI, there is an increase in operating speed of circuits.

The Downside of VLSI are High level of knowledge and skills are required in electronics related fields to understand VLSI technology.

Hardware Languages in VLSI

• In VLSI, the programming languages used for Integrated Circuit designs are called Hardware Description Languages.
• The Hardware Description Languages (HDLs) include VHDL, Verilog, System Verilog.
• HDL used for different architectures allows the design to be simulated earlier in the design cycle in order to correct errors.
• The most common HDL used for integrated circuit design are Verilog HDL and VHDL.
• Whereas in Embedded systems are based on microcontrollers. Embedded system design, use to develop field-programmable gate array (FPGA) based embedded applications

In embedded systems, the microcontrollers or microprocessors perform specific tasks, so digital system designs increase the performance and reliability of the product.

Verilog Basics:

Verilog is a hardware description language, used to provide a high level of software programs that a microprocessor executes.

Verilog is used as an input for synthesis programs which will generate a gate-level description for the circuit. Some Verilog constructs are not synthesizable, so it effects the size and speed of the synthesized circuit.

It also defines constructs that can be used to control the input and output of simulation. Verilog has a better grasp on hardware modeling but has a lower level of programming constructs. Verilog is not as verbose as VHDL so that's why it's more compact.

There are four levels of abstraction are

1.Algorithmic level

2.Register transfer level

3. Gate level

4. Switch level

VHDL Basics:

VHDL(VHSIC-HDL), is Very High-Speed Integrated Circuit Hardware Description Language.

VHDL is more verbose than Verilog and it is also has a non-C like syntax. With VHDL, you have a higher chance of writing more lines of code.

VHDL is a hardware description language that can be used to model a digital system. The digital system can be as simple as a logic gate or as complex like computer chips.

It is used in electronic design automation to describe digital and mixed-signal systems such as Integrated circuits.

The digital system or structure is made up of large modules, and within each module there is a flow of instructions like a software program with variables, control flow, conditionals and loop.

Each module has one or more inputs along with one or more outputs.  The inputs are specified within a structure called an entity.

VHDL provides different types of constructs called design units. They are entity declaration, architecture body, configuration declaration, package declaration and package body.

Concepts in VLSI:

• Digital electronics is basic building concept focused in VLSI.
• Combinational & Sequential Circuits, Logic gates and Finite State machine are used in digital electronics.
• VHDL/Verilog uses in system programming.
• The scripting language uses either Perl or TCL.
• Verilog/System Verilog work on building verification using Methodologies like UVM/OVM.