Combinational Circuit MSI Circuit

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Combinational Circuit MSI Circuit

• ENCODER
• With the aid of K-map (dont care situation), we
  can get
• D0 F1 F2
• D1 F2 F3

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Combinational Circuit MSI Circuit

• ENCODER (Octal to Binary)
• At one time, only one input line has a value of 1
• Most of the time needs priority encoder

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Combinational Circuit MSI Circuit

• ENCODER (Octal to Binary)
• Can you get 2n to n encoder without using
  Karnaugh map

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Combinational Circuit MSI Circuit

• DEMULTIPLEXER
• Given input line sets of selection line,
  demultiplexer will send data directly from input
  to selected output line
• Example 1 to 4 Demultiplexer

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Combinational Circuit MSI Circuit

• DEMULTIPLEXER
• Demultiplexer is similar to decoder with enable
  as follows

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Combinational Circuit MSI Circuit

• MULTIPLEXER
• multiplexer is a device which consist of
• Several input line
• Several select line
• One output line
• It transmit one from 2n input line to one output
  line using n select line. It is also known as
  data selector

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Combinational Circuit MSI Circuit

• MULTIPLEXER
• Truth table for 4-1 multiplexer

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Combinational Circuit MSI Circuit

• MULTIPLEXER
• Output for multiplexer is Sum of the (product of
  data lines and selection lines)
• Example Output for 4-1 multiplexer is
• 2n-to-1 line multiplexer or 2n1 MUX is made from
  n2n decoder with 2n input line added, for each
  AND gate.

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Combinational Circuit MSI Circuit

• MULTIPLEXER

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Combinational Circuit MSI Circuit

• MULTIPLEXER
• Usage

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Combinational Circuit MSI Circuit

• LARGE MULTIPLEXER
• Large multiplexer can be built from smaller
  multiplexer
• 81 multiplexer can be built from smaller
  multiplexer like this

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Combinational Circuit MSI Circuit

• LARGE MULTIPLEXER
• Other example the building of 81 multiplexer
  from smaller multiplexer

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Combinational Circuit MSI Circuit

• LARGE MULTIPLEXER
• 161 multiplexer can be
• built using five 41
• multiplexer

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Combinational Circuit MSI Circuit

• MULTIPLEXER (Function Execution)
• Boolean Function can be executed using
  multiplexer
• 2n1 multiplexer can execute Boolean function
  with n input variable as the following
• Expression in SOM
• Example
• Combine n variable to n selection line
• Put 1 at data line if it is a minterm for that
  function, else 0

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Combinational Circuit MSI Circuit

• MULTIPLEXER (Function Execution)
• This method succeed because
• Put 1 at I1,I2, I3, and 0 at the remaining

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Combinational Circuit (Programmable Logic Device)

• Read-Only-Memory (ROM)
• Semiconductor memory is a device where data can
  be stored and fetched
• Logically, this memory device can be said as
  memory cells table (data)

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Combinational Circuit (Programmable Logic Device)

• Read-Only-Memory (ROM)
• ROM is a memory device where data can only be
  read but cannot be written
• Writing is done by special programming device
  (programmable ROM)
• Any Boolean function can be executed by using
  ROM. The steps Get TT, take its input as address
  and output as data
• Advantage Boolean function is executed directly
• Disadvantage Didn't use the dont care and
  variable input numbers is limited (e.g. 10 input
  1K, 16 input 64K, 20 input 1M)

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Combinational Circuit (Programmable Logic Device)

• Read-Only-Memory (ROM)
• Ready-made ROM Device Type
• ROM Read Only Memory
• Data is written to memory by mask programming
  when manufacturing process. High cost to start
  and very cost effective if produced in large
  quantity
• PROM Programmable ROM
• Semi-custom chip. Fuse can be burnt with
  special hardware programming unit. High cost
  for small quantity and it cannot be erased after
  programmed.

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Combinational Circuit (Programmable Logic Device)

• Read-Only-Memory (ROM)
• Ready-made ROM Device Type
• EPROM Erasable PROM
• Similar with PROM only that data can be erased
  by exposing it to ultra violet light
• EEPROM Electrically EPROM
• PROM where data to be erased can be selected by
  hardware programmer unit other than ultra
  violet light. Very useful for isolated device
  where it can be reprogrammed from far

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Combinational Circuit (Programmable Logic Device)

• Programmable Read-Only-Memory (PROM)
• Device with hardwired AND array (i.e. decoder)
  and programmable OR array
• AND array (decoder) execute 2n minterm product
  combination for n input (known as n2n decoder)
• n line input and m line output
• Input bit variable combination address
• Input bit combination for output line word
  (each word contain m bit)

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Programmable Read-Only-Memory (PROM)
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Programmable Read-Only-Memory (PROM)
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Programmable Read-Only-Memory (PROM)
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Combinational Circuit (Programmable Logic Device)

• Execute logical function with PROM
• Example (8X3 ROM)
• First, convert each function to SOP

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Execute logical function with PROM
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Execute logical function with PROM