8-to-32 line decoder with 4 to 16 line decoder

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mohandsyasser

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Dear,
I want to construct a 8-to-32 line decoder with four 4-to-16 line decoders with enable

i have 4-of-16 decoder/demultiplexer with input latches

is there is a 8 to 32 dec ? i need his data sheet
 

Hi,

What chips do you actually have - their code eg 74154 ?

What is the 8 bit source - a micros port ? and how will the data be presented ? - if you can to control the upper and lower nibbles separately then you only need two 4-16 decoders
 

Hi,

Well just two of those chip should give you the 8 to 32 lines you need .

Its how you output the 8 bits of data that matters.

If you can output the data to the parallel port in two separate 4 bit nibbles instead of an 8 bit number.

eg parallel port bit 0-3 as lines 1-16 to decoder 1 inputs
. . . . . . . . . . . . bit 4-7 as lines 16-32 to decoder 2 inputs

If you can only output the 8 bits as a hex number 00 - FF / 0 - 255 then you will need to -

parallel port bit 0-3 to decoder 1 and 2 inputs.
parallel port bit 4 to decoder 1 inhibit and decoder 2 inhibit via an inverter

This will let decoder 1 output 1-16 and when bit 4 goes high decoder 1 is switched off and decoder 2 displays 17-32.
 

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