Gate Array Design - Computer Science - Lecture Slides, Slides of Computer Science

These are the Lecture Slides of Computer Science which includes Bit Adder, Code, Vector, Bcdcarryout, Architecture Behavioral, Component, Signal, Waveform, Logic etc. Key important points are: Gate Array Design, Basic Transistors, Cells, Function, Advantages, Reduced Design Time, Less Chance of Errors, Reduced Production Costs, Decrease Time to Product, Universal Logic

Typology: Slides

2012/2013

Uploaded on 03/23/2013

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Gate array design
Use a sea of basic transistors (pmos/nmos) or
gates (NAND/NOR)
• Can have cells which can provide a universal logic
function
• Just need to add signal routing only a few masks
Advantages:
• Reduced design time
• Less chance of errors
• Reduced production costs
• Decrease time to product
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Gate array design

  • Use a sea of basic transistors (pmos/nmos) or gates (NAND/NOR)
  • Can have cells which can provide a universal logic function
  • Just need to add signal routing – only a few masks

Advantages :

  • Reduced design time
  • Less chance of errors
  • Reduced production costs
  • Decrease time to product

www.geocities.com/aps_ipu

Programmable design

  • Use an array of logic cells
  • Cells can provide a universal logic function
  • Signal routing through switch box approach
  • RAM holds routing patterns (re-

programmable)

Advantages :

  • Reduced design time
  • Easily reworked
  • Low design costs
  • Decrease time to product

Disadvantages :

  • Limited flexibility
  • Low volume production
  • Less easily protected IPR
  • Programmable switches allow connections

to be made in an array of logic gates. We will look at the operation of each and examples of combinatorial and sequential design with each.

Programmable Logic Devices

(PLDs)

What are the advantages of programmable logic devices?

  • simple PLDs can realise from 2 to 10 functions of 4 to 16 variables on a
  • single integrated circuit
  • excellent for prototyping designs
  • it is possible to replace a number of SSI devices with a single device to
  • realise logic networks

Programmable Technology

∗ Fusible link devices - e.g. the PROM

  • Blowing a fuse breaks a link between lines
  • Once programmable
  • Very high density possible ∗ Electrical switching elements - e.g. the EPROM, EEPROM
  • nMOS transistors used to ‘switch’ connections between lines
  • Devices can be re-programmed
  • Relatively high density
  • How do we program PLDs?

Structure of PAL

Structure of a FPGA

Configuration of Memory Cell

Programmable I/O

General Purpose Interconnect

Vertical and Horizontal long line

EPROM Programmable Switches