Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

8.2.1 GPIB Bus (IEEE-488)

 

· A Parallel bus that has been enhanced to support a number of computers connected by the same cable.

 

· A Brief History,

  1. · In the early 70's there was a movement towards standard serial interfaces, but no clear development of a parallel interface standard. As a result Hewlett Packard (HP) set out to develop the GPIB (General Purpose Interface Bus).
  2. · The HP standard was accepted by both the IEEE and ANSI as standards in 1975.
  3. · By the early 80's the standard was available in small personal computers (e.g. Commodore Pet Computers).
  4. · Today many products, and chips are available for development and use of the standard.

 

· Advantages,

  1. - Low costs
  2. - Widely available for test instruments
  3. - Maximum speeds between 500 Khz and 1 MHz
  4. - Can replace up to 16 individual serial interfaces with a single interface on the main computer

 

· Disadvantages,

  1. - Not necessarily real time,
  2. - Can be difficult for beginners to learn the bus architecture, but users are often isolated from this.
  3. - This is often used as a high performance interface on specialized equipment, but is not available on commercial applications anymore.

 

· Some details,

  1. - Each device on a GPIB bus has its own address number.
  2. -A talker-listener protocol is used to resolve bus usage
  3. - The devices on the bus can be instructed to identify themselves.