Combinational Circuit MSI Circuit ENCODER With the aid

Combinational Circuit – MSI Circuit ENCODER • With the aid of K-map (don’t care situation), we can get D 0 = F 1 +F 2 D 1 = F 2 +F 3 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 1

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 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 2

Combinational Circuit – MSI Circuit ENCODER (Octal to Binary) • Can you get 2 n to n encoder without using Karnaugh map MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 3

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 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 4

Combinational Circuit – MSI Circuit DEMULTIPLEXER • Demultiplexer is similar to decoder with enable as follows: MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 5

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 2 n input line to one output line using n select line. It is also known as data selector MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 6

Combinational Circuit – MSI Circuit MULTIPLEXER • Truth table for 4 -1 multiplexer MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 7

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 • 2 n-to-1 line multiplexer or 2 n: 1 MUX is made from n: 2 n decoder with 2 n input line added, for each AND gate. MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 8

Combinational Circuit – MSI Circuit MULTIPLEXER MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 9

Combinational Circuit – MSI Circuit MULTIPLEXER • Usage: MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 10

Combinational Circuit – MSI Circuit LARGE MULTIPLEXER • Large multiplexer can be built from smaller multiplexer • 8: 1 multiplexer can be built from smaller multiplexer like this MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 11

Combinational Circuit – MSI Circuit LARGE MULTIPLEXER • Other example the building of 8: 1 multiplexer from smaller multiplexer MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 12

Combinational Circuit – MSI Circuit LARGE MULTIPLEXER • 16: 1 multiplexer can be built using five 4: 1 multiplexer MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 13

Combinational Circuit – MSI Circuit MULTIPLEXER (Function Execution) • Boolean Function can be executed using multiplexer • 2 n: 1 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 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 14

Combinational Circuit – MSI Circuit MULTIPLEXER (Function Execution) • This method succeed because • Put 1 at I 1, I 2, I 3, and 0 at the remaining MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 15

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) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 16

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 “don’t care” and variable input numbers is limited (e. g. 10 input – 1 K, 16 input – 64 K, 20 input – 1 M) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 17

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. MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 18

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 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 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 19

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 2 n minterm product combination for n input (known as n: 2 n 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) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 20

Programmable Read-Only-Memory (PROM) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 21

Programmable Read-Only-Memory (PROM) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 22

Programmable Read-Only-Memory (PROM) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 23

Combinational Circuit (Programmable Logic Device) Execute logical function with PROM • Example (8 X 3 ROM) – • First, convert each function to SOP MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 24

Execute logical function with PROM MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 25

Execute logical function with PROM MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR 26