8-line-to-3 line Priority Encoder

IC 74LS148

Prosperties:

• Active low in8 &Active low out3(output component code of binary)

• With one Enable input (Active-low)

• With one Enable output (Low while EI “0” and all ins “1”)

• With one GS

• 大数youxian

Extentions

1.to 16 line-to-4(EO to GS)Encoder

Decimal-to-BCD Priority Encoder

IC: 74HC147

Prosperities

Multiplexers(MUX) &Data Distributors(DEMUX)

Prosperities

• 4 Send ports

• 1 Transmission line as connection (BUS)

• 4 Received Ports

MUX

Logic symbol:4-input Multiplexer

• 2x Data select ports : S0 S1.   called “Address”

• 4x Data inputs:D0-D3

• 1x Data output: Y

8-input Multiplexer

• 3x selects

• 8x inputs

• 1x output

Extensions

Implement almost all Logic Functions in MUX(Based on SOP format)

真值表对应作图 地址端口少一或一致

Methods:Enable inputs->active

Address

MUX->forms of N-1/N

16-inputs Multiplexers using 2x 8-inputs

IC 74HC157

• 4x MUXs (per 2 seletors)

• used in 2x (4-bit binary) selection

• Common Control Panel

  * 1x Enable for all MUXs——

  * 1x Data selector port——–

Extensions

1. A 7-segment Display Multiplexers

DEMUX

译码器就可以实现功能

Parity Generators/Checks 奇偶发生/校验器

IC: 74LS280

Error Detection

Tips

MSB = 8 ,while LSB=1