ASIC/FPGA Design

What is ASIC?

# ASIC stands for application specific integrated circuits (IC). Lets first look at a general purpose IC.

# ICs are set of electronic circuits on a chip of semiconductor material, normally silicon. They are classified in terms of size, for example:

-> SSI – small scale integration – 1-10 gates – few tens of BJT

-> MSI – medium scale integration – counters

-> LSI – large scale integration – microprocessors

-> VLSI – very large scale integration – 64 bit microprocessors, with cache, floating FUs – over a million BJT

# Earliest ICs were based on BJT. Then n-channel MOS was widely used. Currently, most ICs are based on CMOS.

# Standard ICs can be found in books, for example, 7400 IC has four NAND gates, 7404 IC has six NOT gates.

# A microelectronic system with few custom IC is better than with a lot of standard ICs. Thats why, application specific ICs or ASICs are commonly used for high speed applications, such as, for telecommunications ICs.

What is FPGA?

# FPGA stands for field programmable gate array.

# FPGA chip is configurable or programmable. It is built with programmable logic blocks (PLB) and interconnects

# The FPGA chip comes in a circuit board which also includes memory chips, external connectors and displays.

# Most recent FPGA boards comes with ARM processors also making it a complete system-on-chip (SoC).

# The word "field" is used because the device function can be modified ”in the field”/at site where device is installed

This is how a real life FPGA looks now-a-days. The main FPGA chip is in the middle with VIRTEX-7 written on it.

VHDL

VHDL is a very popular hardware description language (HDL) to design ASIC and FPGA.

A myriad of tutorial and lessons to learn VHDL are available online. It is easy to get lost in this sea of lessons and I have always found it difficult to find a concise resource including the most important lessons. On the other hand, most comprehensive resources are so elaborated that it becomes boring after a certain stage. I created a website for learning VHDL where I tried to compile a list of VHDL lessons and my own explanation. The website can be accessed through this link:

LEARN VHDL

A myriad of tutorial and lessons to learn VHDL are available online. It is easy to get lost in this sea of lessons and I have always found it difficult to find a concise resource including the most important lessons. On the other hand, most comprehensive resources are so elaborated that it becomes boring after a certain stage. I created a website for learning VHDL where I tried to compile a list of VHDL lessons and my own explanation. The website can be accessed through this link:

What can be found here

1. My own written explanation of various topics on VHDL.

2. A few building blocks or links to building blocks of VHDL.

3. Some useful books and lectures to learn and use VHDL.

Target Audience

The target audience of this site are students/researchers/professionals who have very limited to no knowledge of VHDL. This site is not aimed for advanced users of VHDL, even though they might find this site useful. This is not a comprehensive site that includes all the possible lexical syntax or rules of VHDL. We only include the rules and syntax necessary for a beginner.