Multiplexer?

[axro]

If I wanted to drive 3, 7-segment displays and have 3 inputs connected to an AVR using the least amount of pins, would a multiplexer help me do that? Or would I use a multiplexer?

 

[Pommie]

To drive 3 seven segment displays only requires 10 pins. A multiplexer wouldn't help. A BCD to seven segment decoder would reduce it to 7 pins.

Mike.

 

[axro]

When then would you use a de/multiplexer?

 

[Pommie]

If you were driving 8 seven segment displays then you might use a 3 to 8 demultiplexer (eg 74138) to drive each display.

Maybe you are confusing things. The AVR would in fact be multiplexing the display and so would, in effect, be a multiplexer.

Mike.

 

[karuppiahsaravana]

Dear Sir,

I need circuit for measuring capacitor in 100pf to 400pf variable.

 

[axro]

Thanks Pommie.

Slightly off-topic. Correct me if I'm wrong, but a Shift Register is alot like a multiplexer(actually prob more like a demultiplexer) but it uses serial to communicate correct?

 

[misterT]

Multiplexers, Shift registers and Decoders are all different kind of devices. All solutions discussed here so far are Decoders.

I used serial to 8bit parallel shift registers in a big 7-segment clock project recently. Shift registers allow you to easily add more segments to the construction when needed. I had an AVR to drive the display.

 

[Mike - K8LH]

I too am a fan of serial-to-parallel latch or driver ICs.

Regards, Mike