CSCI 255, ENGR 274, ECE 212 -- 21 September, 2000

Announcements

• Homework 2 solution
• Homework 4
• Test -- 28 September, 2000

Programmable Arrays

• Logic devices
  • PAL -- programmable array logic
  • PLA -- programmable logic array
• organization of a k × n × m PLA
  • k inputs
  • n ANDs (really NANDs)
  • m ORs (really NANDs)
  • some also have m XORs at the outputs
• Tools and Techniques
  • personality matrix
  • programming the device
• Examples
  • Texas Instruments Impact-X
  • Texas Instruments EPIC
  • Xilinx CPLD

MSI-like components

Multiplexers and selectors

• typical configuration include
  • 2^m data inputs
  • m selector outputs
  • 1 data input
  • But may be grouped
• typical chips include
  • Dual 4-to-1 selector

Decoders and Demultiplexers

• typical configuration include
  • m data inputs
  • 2^m data outputs
  • 1 enable input
• typical chips include
  • 3-to-8 decoder